DX vs. FX: It's Not a Debate, It's a Choice

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A friend of mine recently took a step into a brave new world of digital SLR photography when she shelved her point-and-shoot camera and purchased a Nikon D5300 and kit lens. The purchase was not without an amount of trepidation: confusing controls, buttons everywhere, multi-function interfaces, knobs, an interchangeable lens, and increased size.

For many customers, moving from your camera phone or compact point-and-shoot to a larger and more complex photographic tool is a big decision. Some immediately feel at home with the DSLR, and others never get past what can be an intimidating technological leap.

Within a few days of purchasing her new camera, a friend of hers, a "professional" photographer, did exactly what a friend/mentor/advisor encouraging a shy new photographer entering the DSLR world probably should not have done. He told her that she had purchased the wrong camera. Why? Because the Nikon D5300 has a smaller than full-frame sensor, what Nikon calls its "DX," sensor. "You should have gotten an FX (full-frame) camera," he told her.

"DX" and "FX" are Nikon's designations for the size of the cameras' sensors. It was not very long ago that all DSLR cameras came with sensors whose dimensions were smaller than a frame of 35mm film. However, things have changed, and photographers may now purchase DSLR cameras with "full-sized" sensors from Canon, Nikon, Sony, and others. Once the sensors grew in size, the debate over sensors grew in volume. For the purposes of this article, I will use the Nikon DX/FX nomenclature to refer to the sensor sizes, but the reader should be aware that this discussion applies to any manufacturer who makes 35mm equivalent full-frame and cropped-frame sensors. For example, Canon's cropped-sensor lenses, in Canon nomenclature, are known as EF-S.

A Nikon DX sensor (left), compared to Nikon FX sensor (right).

My friend was immediately filled with self-doubt after having made a sizable financial investment in her new camera. Should she return the camera to the store and spend more on a larger and more expensive camera that requires more expensive lenses, or should she just retreat from DSLR photography altogether and use her new D5300 as a paperweight?

If you, like many photographers, have been inundated with blogs, chats, and editorials about this issue, you are likely on your way to being firmly entrenched in the FX side of the camp, as the DX stalwarts are becoming few and far between.

No need to panic, DX fans! There are many out there who still enjoy the benefits of the DX sensor while living, happily in many cases, with its drawbacks.

PROS AND CONS

FX Sensor
Pros Cons
Low-light performance/Image quality - directly attributed to larger pixels Higher Price
More control over depth of field because you have to get closer to your subject Size (the full-frame cameras are generally larger and heavier - there are exceptions)
"True" angle of view/focal lengths - No conversion needed Cannot use lenses designed for smaller sensors without cropping to the smaller image
Higher dynamic range Image quality - by using a large portion of the lens image circle, edge softness and vignetting can occur
DX Sensor
Pros Cons
Lower Price (cameras and DX lenses) Low-light performance inferior to FX
Size (usually smaller and lighter cameras) Smaller dynamic range
"Telephoto" effect (a 200mm lens is virtually a 300mm lens) General lack of "super-wide" lenses
Versatility - uses specially designed smaller lenses as well as all "normal" lenses Smaller viewfinder image
Image quality - captures image closer to the center of the image circle. This usually offers more sharpness and less vignetting (darkening) around the edge of the frame  

Moving away from the technical differences and impassioned sales points in the battle between the FX and DX sensors, I feel that photographers hoping to educate and inspire new photographers should steer clear of telling other photographers that they are "wrong" simply because they purchased a DX-sensor camera.

My father used to tell me, "Some of the world's greatest photographs were taken with a cardboard box (pinhole camera)."

My father used to tell me, "Some of the world's greatest photographs were taken with a cardboard box (pinhole camera)." This is true. Pulitzers have been won with photos taken with $20 plastic cameras. Point-and-shoot disposables have captured exquisite beauty.

The camera is a tool used to gather light. And, like any tool, there are different cameras for different jobs. The DSLR might be the photographic equivalent of a pocket-sized multi-tool, but it is not always the right camera for every job. Continuing that thought process, there is not only a market for the DX sensor cameras, there are real-world benefits to their operation and those fans of DX should not be criticized for their choice of tools.

So, if you are shopping for a new DX DSLR camera, or you are a fan of the DX sensor and its advantages, know that there is no reason to bury your head in the sand or feel envy when someone comes by with their FX machine—the world will keep spinning about its axis. Meanwhile, go out and create some great photographs with your camera—regardless of the sensor size.

830 Comments

Hi Todd

I presently own a Nikon D5300 camera and want to upgrade.  I have been considering both the Nikon D750 and the Nikon D500.  There seems to be advantages to both cameras,  which would you suggest?

Hi Jay,

Great debate there. They are both awesome cameras, so the real decision hinges on what lenses you have (or want to get). If you have a battery of DX lenses that are working well for you, I would stick with the DX D500. If you have non-DX lenses, you could move over to full-frame fairly painlessly.

My guess is that the D500, as a DX-version of the D5, is going to be a bit more robust physically and faster internally (focus and processor) than the D750...if speed and durability are important to you.

What lenses do you have and what kind of photography do you do, Jay?

Hi Todd

Thanks for the great article, this gave me some reassurance that i might not be that badly off with my dx camera.

I'm currently looking into buying a new Lense, and this  time i want a Pro lens and i'm willing to drop 1-2K for it. My Question to you is, should i spend the extra and buy a Fullframe lense, or should i buy a DX one? With the fullframe lense i'd have the option to  continue using the lense if i ever were to swtich to FX. And there are no real disadvantages of using a FX lens on a DX camera, right? I heard somewhere that the fx lenses are generally better because they let more light through (therefore also more expensive, bc more glass is needed for the bigger sensor) so wouldn't that just be a big advantage to buy a fx lens for my dx camera? (i couldn't care less about the additional weight).

Or should i just stick with DX lenses, and if so, why?

Hey Martin,

I really hope you aren't bad off with an APS-C camera because that is what I use!

Great question about your next lens. So, yes, if you buy a non-DX lens, you can use that in the future if you have a full-frame camera. If you get a DX lens, you likely won't want to use that on a full-frame camera as you will get severe vignetting.

If you don't care about size/weight and cost, then you could easily go with a non-DX lens. The advantage of the DX lenses is that they are (generally) lighter and smaller. I assume you are shooting Nikon because you use the DX/FX vernacular. The non-DX 24-70mm f/2.8 lens is a giant of a lens and very heavy whereas the DX 16-80 f/2.8-4 lens is light and portable and covers a wider zoom range at the expense of one stop of light at the telephoto end. [I reviewed that lens here: https://www.bhphotovideo.com/explora/photography/hands-review/nikon-af-s-dx-nikkor-16-80mm-f28-4e-ed-vr-lens?form=reply&pid=648301]

A non-DX lens will "futureproof" you, but I personally prefer smaller and lighter. The choice is yours. Please let me know if you have follow-up questions and thanks for stopping by!

I thought I'd mention another option.  The Nikon 17-55 f2.8 for dx. It's the dx version of the 24-70. It is a "pro" lens for dx; the only Nikon pro lens for dx I believe. Yes, it's heavy and yes, it's expensive but for many it's a wonderful lense. I absolutely love it.

You do trade VR for a constant f2.8. That's something to consider depending on your typical use. In terms of weight I actually prefer the heavier lense as I find that I have a steadier hand with it. Regarding the price: you can find excellent used copies on the market.  I picked mine up for under $500 with no signs of use and not even a speck of dust internally. 

Critics love to disregard this lense because they refuse to justify paying "pro" prices for a dx lense but if you look at user reviews you'll find a large, very happy, following. 

Do your own research. Maybe this is an option for you, maybe it isn't. 

Hi Travis,

Great tip! And, that lens can be found on the used market for good prices. I should know...I used one for years—it was my workhorse—and sold it for not a lot a few years back.

Having said that, I really really liked the 16-80. Yes, you do lose the constant f/2.8, but the size and weight and sharpness of the newer lens goes a long way for me!

Thanks for stopping by and helping a fellow B&H customer! Happy Holidays!

Hi Todd - Trying to decide the next set of lens to buy, beyond the kit lens.  Options include: a) f/1.8 35mm, 50mm and 85mm and b) Sigma 18-35mm f/1.8 ART Lens and may be another that's a zoom lens that take me into the 85-150mm range.  Is there a recommendation on what to upgrade to beyond the kit lens from you?  Thank you..

Hey Eman,

Good question. Sorry for the delay in replying...I was on vacation.

I always recommend that DX 35mm f/1.8...that is likely the best lens for the money you can get for Nikon DX...and I am a big fan of the "Nifty 50" [https://www.bhphotovideo.com/explora/photography/buying-guide/the-one-lens-every-photographer-should-have-and-use-the-50mm].

The Sigma ART zoom is intriguing as well, but it might be on the bigger/heavier side for DX. A 50mm on DX makes for a nice portrait lens as does the 85mm (FX and DX). You cannot go wrong with any of your options, but if you were one of my photo students, I would tell you to to go with the primes and get closer to your subjects!

Standing by for follow-ups and, again, I apologize for the delay.

Very informative, if digressive, thread on DX vs. FX. Also slightly off-topic, but:  How can I tell if out-of-focus images are the result of camera damage vs. user error? I dropped my D7200, sent it back for repair of the autofocus system. After repair, some images with 70-300 kit lens are in focus, others not.  (I shoot lots of birds, wildlife, etc., so always dealing with leaves in the foreground, etc.) I can't tell if it's because the autofocus is working only sporadically, or the whether I need to practice more on the various autofocus modes, number of focus points, etc.  Any suggestions about how to track down where the problem lies?

Hey Lance,

Thanks for the kind words on the article and thread!

Good question here.

If the camera was repaired correctly, you should be good to go, but that is always an "if," unfortunately.

As you stated, there are two possibilities: camera error or user error.

To test for both, you could "bench test" your D7200 and 70-300 lens on a static target while mounted on a tripod. If the focus is accurate there, you are close to eliminating the camera error part of the equation, but not totally. The next test would be in a more controlled environment on a moving target. Try to set to the most basic autofocus mode and keep the focus point in the center. If the camera passes that test, you are probably down to user error, unfortunately.

Just like I mentioned to Joy in the next thread, today's AF systems are really complex and have a lot of options. We haven't tried to write an article about it because the systems vary from camera to camera, even from the same manufacturer. Therefore, I would recommend scouring the web for a D7200-specific AF tutorial to see if that helps.

I hope this gets you started down the right track. Let me know if you have more questions and how the testing goes, if you do test.

Thanks for stopping by!

Hello Todd,

Thanks for this article! I have a Nikon D5500 but sometimes feel it's limitations with low light capabilities, depth of field, and clarity. I have some upcoming travels, and was wondering if I should invest in an older (D610) FX body, (but then budget wise, I won't have money for prime lenses for awhile), or if I should get a good prime lens (I have the 50mm 1.8 but want more!) like the Nikon 24-70 2.8 and just use it on my DX body until I can afford the FX body. Or, another option is, I have found a good deal on a used Nikon 24-70 2.8, or alternatively I could get the Sony A7iii with the 24-70 3.5-5.6 kit lens. I feel torn by the options and would appreciate your expertise! I am looking at photographing my young (sometimes fast moving) kids/family and the scenery. Thank you in advance for any help! 

Hi Joy,

Thanks for the questions! I see you are feeling the gravitational pull of full-frame!

If you haven't been using it heavily, the D5500 and your 50mm f/1.8 is a potent combination and you will find a clarity and shallow DOF that kit lenses only dream about. That is an immediate solution to your limitations and one that doesn't require a new purchase.

The D610 is a great camera, and a used FX camera is a fairly economical way to get your feet wet in full frame. The 24-70 f/2.8 is a great lens, but super heavy and large..especially on the D5500. But, it will certainly be an upgrade to any kit lenses you might be using. Having said that, the old joke is: instead of a 24-70mm f/2.8, just get a 50mm and take a few steps forward or backwards...zoom with. your feet!

Switching to mirrorless is certainly an option, but you will be basically starting from scratch. If you can afford it, by all means, go for it! Based on what I am reading, you will want to move past the kit lens there as well...another expense to consider.

The future-proof choice might be to get that 24-70 and shoot that and your 50 on the D5500 and see if you like that. Then, when/if you switch to FX, you will have two core lenses already.

Let me know if you have follow-up questions! Thanks for stopping by!

Thank you so much for your quick response. I really appreciate your advice. Can I ask another question? I love the 50 1.8, but when I go to edit my pictures I notice that half are clear, and the other half out of focus or the camera has focused on the background instead of the subject. Is this due to something I am doing, or could there be a problem with my camera or lens? 

Hi Joy,

No worries!

So...I hate to say this out loud, but missed focus is usually "user error" and not the camera or lens. Modern autofocus systems are overly complex—you used to just put the center of the frame over what you wanted in focus and presto! Done!

Today, "intelligent" AF systems try to evaluate the scene and figure out what you want them to focus on. Sometimes they work and sometimes they fail miserably.

We would have written an autofocus tutorial on Explora long ago, but the systems change from camera to camera and manufacturer to manufacturer. Its a moving target that we aren't trying to hit. That being said, search the web for Nikon D5500 autofocus tutorials and you'll likely find a good video or two on the system.

Let me know if you find something helpful and if you have specific questions!

lol, I had the impression that might just be the issue. Thanks for your honesty. I will do that. Thanks again for your expertise. You have been so helpful. I hope you don't mind if I bug you again some time. Many thanks again!

Hi Joy,

No worries at all! And, please don't hesitate to reach out! I am here to help!

Standing by to be bugged!

Sorry, I am back sooner than I thought. I took my camera into a shop to test out some lenses to discover that it back focuses. The lenses can't be calibrated because it's a D5500 and is not an option on my camera body. Can I ask your opinion- time to get a new camera body, or try and get it fixed? If I do go for a new camera, do you suggest mirrorless? Thanks!!

Hey Joy,

Sorry for the delay in replying! I didn't check the "mail" yesterday. :(

I guess I have to eat some crow for suggesting it might be user error! Sorry!

So...the fix might be expensive, but you might want to call Nikon to see if you can figure out what they charge for that. If the fix is pricey, it is going to be time for a new camera.

As far as a new camera, I am a fan of mirrorless. I love the ability to see the exposure and white balance before I take the shot. It is cheating...pure and simple! I also like the smaller sizes of mirrorless cameras—especially APS-C mirrorless. The days of a heavy camera bag are gone for me!

If you want to stick with Nikon, the Z6 and Z7 are popular and getting great reviews.

Standing by for a reply...sorry, again for the delay and misdiagnosing your (camera's) issue!

lol, not at all. My first thought was also that I was doing something wrong! I had been having trouble with a lens and when I took it in they were able to tell me that the camera was back focusing. Can I ask what mirrorless camera you suggest? Nikon/Sony/Canon? Thanks!

Hey Joy,

Good morning!

Before I answer your brand question, I would ask you to tell me what lenses you have for your Nikon system currently. That will help me give a better answer.

Cheers!

I have a few DX lenses- the 55-300 4.5-6.5 (that is having focusing problems, and I'm sending it in to Nikon since it is still on warranty), the 10-24 3.5-4.5, and the 50mm 1.8. 

Hey Joy,

Thanks for the info. If you switched to Nikon full-frame mirrorless, the only lens that comes with you is your 50mm f/1.8. The others will be retired. Getting almost all new lenses is a non-negotiable financial consideration.

Brands, for the most part, are on equal footing these days. The disadvantage of switching is that you need to get used to new controls, menus, and quirks in addition to getting all new lenses and accessories. Here is another consideration: size and weight. While the full-frame mirrorless cameras are lighter and smaller than their full-frame DSLR counterparts, the lenses are not smaller and lighter (or less expensive). Neither you, nor your back, will forget the first day you carried a 24-70mm f/2.8 lens around all day!

Fantastic full-frame image quality comes at a cost financially and in size/weight.

If you are happy with the photos you have been getting with your DX/APS-C sensor, I would suggest that you invest in more-better lenses like the DX 16-80mm f/2.8-4 [My review here: https://www.bhphotovideo.com/explora/photography/hands-review/nikon-af-s-dx-nikkor-16-80mm-f28-4e-ed-vr-lens].

The other option is to switch to a brand that specializes in APS-C mirrorless—Fujifilm. With Fujifilm, you get the advantage of small/light mirrorless cameras with smaller APS-C specific lenses. Check out my review of the X-T30 here: https://www.bhphotovideo.com/explora/photography/hands-on-review/what-aps-c-mirrorless-should-be-the-fujifilm-x-t30

That is a lot to digest, so standing by for follow-ups!

Hello Todd! I stumbled upon this very helpful article due to my personal battle between upgrading to a D500 or D800-850. I currently use a D5xxx series (so DX) with a 150-600mm tamron g2 and a few other lenses, but I am mainly concerned about the camera in use with the 150-600mm.

I do wildlife photography, which the camera would primarily be used for... but I cannot for the life of me decide which would be the best at this focal length. I understand that DX virtually magnifies the focal length through cropping it, but would cropping the image of an FX lens to get the same virtual zoom as the DX lens sacrifice too much quality? One of the largest challenges I face is being within a good distance of wildlife to get a good shot, so the extra 300mm of focal length at 600mm on a DX (~900mm total) sounds appealing... but many of the specs of the D850 plus the interest of wandering into the FX world also sound dandy. Any insight you may provide would help dramatically, thank you!

Hi Creston,

If I was primarily a wildlife shooter, I would probably stay in the DX world and, let me throw you this curve ball, look at the D500. The D500 is basically a D5 without the FX sensor or vertical grip.

In my head, shooting FX and doing a DX crop is just more work. Would you still get the maybe-kindof-can't-really-tell-without-pixel-peeping FX benefits inside that crop? I don't know.

And, as an APS-C shooter, I really don't feel much of the pull of FX...

That is my $0.02. Please let me know if you have more questions!

I really appreciate your insight and the help the article provided. I have decided to get the D500 since your recommendation and in only the past few hours of playing with it, I love it! Thank you again!

Hi Creston,

Great news! I am glad you are enjoying your D500! How did you get it so quickly?

Hi, Todd: I have a Nikon D3400 which came with two kit lenses: AF-P 70-300mm and AF-P 18-55 (and two Vivitar attachments for the smaller lens, a 2.2X telephoto converter and .43x wide angle converter w/macro). I got the camera over a year ago and have since got a fixed lens AF-S 50mm and AF-S 18-140mm (and the corresponding telephoto and wide angle attachments. Question 1: Since I have the 18-140mm, do I need the 18-55mm or does it serve a specific purpose? Question 2: Crop sensor lenses don’t work well with full sensor cameras, right? Question 3: Is there a compelling reason to switch to mirrorless? I love the Nikon Z7 but have a hard time justifying the nearly $4K cost and I love my current camera.

Hello Peralte,

I apologize for the delay as I was in Japan for business last week.

Thanks for your note! Good questions… 1. You could probably ditch the 18-55 since you have the 18-140 unless you like the size/weight of the 18-55 for some outings. Another consideration: I have seen amazing macro work with the 18-55 and extension tubes. I don’t know if the 18-140 performs the same. 2. You can use the lenses on FX cameras, but the cameras will shoot in crop mode. 3. Mirrorless is the way of the future, but there is no rush to switch. I bet Nikon’s 2nd generation of mirrorless will be even better than the Z6/Z7, but they made a couple of great cameras to start into their FX mirrorless journey. If you love your D3400, there is no need to switch!

Hi Todd,

I am debating which to buy:

What's a good lense for portraits for the D850?

Would this work well? Nikon 50mm AF-S f/1.8G Nikkor Lens?

Thanks!

Hi Charles,

The 50mm f/1.8 is a fantastic lens and I recommend that everyone carry one. https://www.bhphotovideo.com/explora/photography/buying-guide/the-one-lens-every-photographer-should-have-and-use-the-50mm

It will work well for portraits on the D850, but photographers usually prefer lenses around the 85mm or 105mm focal length for portraits with full-frame cameras in order to get a little more working distance between the camera and subject as well as soften the background a bit.

Thanks for your question and thanks for shopping at B&H! Let me know if you have any follow-ups.

Hi Todd,

Thanks for all that you do for us novices.  I have a Nikon D3400 and will be heading to Africa in July. I have the 18-55  and 55-200mm kit lenses but wish to stretch out to 300mm for the safari.  First, do you think I need the added length and second, if so what would you recommend?  Since the D3400 is DX should I restrict my search to DX lenses only?  Thanks in advance for your help.

Rick

Hi Richard,

You are very welcome!

Great questions here. Sorry for the delay in replying...I was traveling last week for B&H.

For an African trip, you really cannot have too much focal length, from what I have heard. 300mm is pretty much the furthest you can go without a second mortgage these days.

If you shoot DX, you can go with DX and FX lenses, so no need to limit yourself to DX.

As far as 300mm lenses, you could get a zoom that reaches 300mm [https://www.bhphotovideo.com/c/product/1275036-REG/nikon_20062_afp_dx_nikkor_70_300mm.html], but that would be redundant with your 55-200. Because of this, you might want to treat yourself to a 300mm f/4 lens. Nikon has 2 versions...the older D version which is excellent (I own one) [https://www.bhphotovideo.com/c/product/207356-USA/Nikon_1909_Telephoto_AF_S_Nikkor_300mm.html]  [Refurbished https://www.bhphotovideo.com/c/product/731041-REG/Nikon_1909B_Refurbished_Telephoto_AF_S_Nikkor.html] and the new Fresnel model [https://www.bhphotovideo.com/c/product/1111442-REG/nikon_2223_af_s_nikkor_300mm_f_4e.html] that is incredibly light and small, but much more expensive.

There is also the weapon-sized Nikon 200-500mm lens. Fantastic, but large and heavy. [https://www.bhphotovideo.com/c/product/1175034-REG/nikon_af_s_nikkor_200_500mm_f_5_6e.html]

And, another large option...a 150-600mm lens. [https://www.bhphotovideo.com/c/search?sts=ma&fct=fct_lens-mount_3316%7cnikon&N=0&Ntt=150-600mm]

Another outside-of-the-box idea would be to get an inexpensive 500mm mirror lens. The downside of this is that you will be stuck at f/8 and manual focus...not so good when it gets dark.

I probably just gave you too many options. Let me know if you have any follow-up questions. Thanks for stopping by!

Hi Todd,

I saw you replying to comments as early as a month ago and I thought I can pour my dilemma out here and see if I can find an answer. Apologies for the long comment.

I purchased a Nikon D7000 back on Black Friday 2014 with 18-55 and 70-200 kit lenses. I was also gifted a 50mm f1.8 AF (75mm on my APS-C) lens by a coworker who was upgrading his gear. But I was new into DSLR photography and I could not commit to learning and practising with it. The bulk of carrying multiple lenses also made me shun the whole idea of DSLR photography. The camera was left in a bag for almost 3 years while I focussed on using my Google Pixel with moment lenses due to the portability I got from it. I shot raw/jpeg in manual and I got decent pictures out of it considering it was a smartphone camera after all.

After all these years when I opened up my bag and checked my D7000 out it was performing fine without any fungus or other issues. I shot a few photos with the 50mm 1.8 AF and it just felt like a breath of fresh air, like I reconnected with a long lost lover. I also researched a bit and came to the conclusion that I could sell my kit lenses and get a 35mm F1.8 lens for my day to day and travel use. with the 50mm F1.8 being my "zoom lens" for portrait needs.

Here's where my dilemma begins, my D7000 is a really old camera (duh) and online quotes for selling my body+kits is coming to below $250 (inc in BHP). Should I sell my D7000 for this cheap and get a newer model (D7200 maybe) before I get into using a DSLR regularly? I usually take both landscape and portrait photographs on my smartphone and I sometimes do take photos in the night when I travel but not on a regular basis. I feel so much more comfortable using it now than I did in 2015 and I feel this time I am learning fast. I just don't to be stuck in a camera that's so far behind in quality/generation that I can't make the most out of it and end up selling my body+kit+35mm lens (that I'm yet to buy) for cheap next year and purchase a new FX/DX camera.

Again, apologies for the length. I await your response.

--

Prasan

Hello Prasannajeet,

No worries! I am still here. Also, no need to apologize for a long question. Context is good!

First off, you D7000 is still a good camera and the latest Nikon APS-C cameras (D7200, D7500, and D500) are not really a full generational leap ahead of the D7000 as far as sensor technology. They will be better, but not super-noticably better. The D500 and D7500 have the same sensor, with the D500 being the truly pro camera as far as speed and ruggedness.

If you are compelled to upgrade, I would go with the D7500 as it is newer than the D7200. I would imagine the D7200 will be upgraded sometime in the near future. I have no specific information, but if you look at the time period between the D7000, D7100, and D7200, you will likely see a pattern developing...unless the D7500 was actually a D7200 replacement. Depending on who you talk to, it might have been.

You won't regret getting the DX 35mm lens. It is inexpensive and great and can replace your 18-55mm if you "zoom with your feet."

I am not sure I am answering your question regarding the upgrade. In summary, if you want to upgrade, step up to the D7500 and don't sweat the FX/DX debate at this time. Or, keep shooting the D7000 and grab a new lens or two that will stay with you when you do upgrade your camera body.

Please let me know if you have follow-up questions! I will be standing by!

Thanks for reading Explora!

[Received via email...]

 Hi Todd,

Somehow, I'm unable to comment to the article.
I want to thank you for the article. I have a different perspective and would like to see if it's correct.

1) FX and DX lens of the same focal length should have the same optical characters. For example, we compare 300 mm FX and 300 mm DX lenses on a DX body. We expect to get the same image in terms of depth of field, compression, and the physical size of the image on the sensor.

2) If we are shooting birds, the size of the bird image is much smaller than a DX sensor. A 24M pixel DX sensor will have greater pixel density than a 24M FX sensor. So, there will be more pixels for the bird from the DX sensor. Does that make a DX sensor better for shooting birds?

It always kind of drive me nuts when people use the 1.5 crop factor to say that a 300 mm lens becomes a 450 mm lens. The optical characteristics is still a 300 mm lens. But if you were to count the number of pixels for a bird, then 300 mm on 24M pixel DX sensor would be the same as 450 mm on 24M pixel FX sensor.

Is this correct?

Thanks,
Luke

Hey Luke,

Thanks for your email.

Your statements:

1) FX and DX lens of the same focal length should have the same optical characters. For example, we compare 300 mm FX and 300 mm DX lenses on a DX body. We expect to get the same image in terms of depth of field, compression, and the physical size of the image on the sensor.

False. Remember, a 300mm lens is a 300mm lens regardless of the camera it is attached to. Also, there is really no such thing as an "FX lens." There are lenses designed for DX cameras and then there are the rest.

So, if someone sold a "DX 300mm lens" and you put that lens on a DX (1.5x) camera, it would have the same field of view as a 450mm lens on a full-frame camera because the DX sensor is capturing a smaller area of the image circle projected by the lens.

A logical question to follow up here would be, "What is the difference between a DX 300mm lens and a 300mm lens that is compatible with a full frame camera?"

The answer is that a DX lens can be designed in a smaller form factor as it does not have to project the same size image circle as a lens for a full-frame camera. Even though they both have a 300mm focal length, the DX lens can be smaller in diameter and have smaller glass elements. This allows DX lenses to be smaller and lighter than the full-frame compatible lenses of the same focal length

2) If we are shooting birds, the size of the bird image is much smaller than a DX sensor. A 24M pixel DX sensor will have greater pixel density than a 24M FX sensor. So, there will be more pixels for the bird from the DX sensor. Does that make a DX sensor better for shooting birds?

Technically, I would say you are correct, but don't get stuck in the weeds here. Yes, a 24MP DX sensor has more pixels per square inch (not a unit of measure used for sensors...but fine for this discussion) than a 24MP FX sensor. So, theoretically, that one bird in the frame will have more pixels dedicated to it on a DX sensor—assuming the bird is the same size in both the DX and FX frame...but that would require the DX shooter to have a 300mm lens and the FX shooter a 450mm lens while standing in the same spot and shooting the same bird....or the FX shooter to be 1.5x closer with the same lens. (Digression alert.)

Anyway, so, yes, a more dense sensor means more pixels per subject of the same size.

However, is this noticeable? Not to your eye and normal magnifications. In fact, you would have to zoom in pretty far...down to the pixel level...in Photoshop to start seeing a difference.

And, pixel density has drawbacks as far as noise performance. More megapixels isn't always the best thing.

It always kind of drive me nuts when people use the 1.5 crop factor to say that a 300 mm lens becomes a 450 mm lens. The optical characteristics is still a 300 mm lens. But if you were to count the number of pixels for a bird, then 300 mm on 24M pixel DX sensor would be the same as 450 mm on 24M pixel FX sensor.

Don't go too nuts. In a sense, people might not be correct, but what they say is a simplification of the truth on a subject when the detailed truth might be confusing to many. Yes, it is still a 300mm lens, but, the field of view makes it a virtual 450mm lens on a DX camera.

The bizarre thing about all of this is that we use focal length numbers (length) to represent fields of view (which are measured in degrees) and we force these numbers and conversions down people's throats when they honestly don't even know (or often care) that a 50mm lens is "normal" and a lower number means a wider lens and a larger number means more telephoto.

Anyway, I hope this helps. Standing by for follow ups!

 

Thanks!

-Todd

Hi Todd,
 
Thanks for putting up with my delay.
 
I have changed FX lens terminology to regular lens.  The attached diagram illustrates what I was trying to say.  The different "field of view" is shown as different size circles.  
 
Other than the size of circles, both lens have the same magnification, depth of field, compression, and the physical size of the image (letter A) on the sensor.  I believe this is what you mean by 300 mm lens is a 300 mm lens, regardless of whether it's regular or DX.
 
To me, field of view is a size/weight/cost issue, not an optical issue.  Optical has to do with magnification, depth of field, and compression.  (You don't have to agree with my definition.  You just need to understand what I'm trying to say.)  But many people confuse "equivalent 450 mm" to mean greater magnification for a 300 mm DX lens.  I believe that to be false.
 
I understand the trade-offs between DX and FX lens.  For example, greater pixel density means more noise.  However, if you are only counting pixels, DX sensor would give you more pixel under the letter A in the attached diagram.  This adds further argument to the greater magnification thinking.
 
I'm writing to you because my friend thinks he will get greater magnification with a DX sensor and DX lens.  I try to tell him the above, but he doesn't believe it.  So, I thought I would verify with you.  I'm not trying to say what is better or worse.  I'm just trying to explain that there is no increase in magnification.  The increased number of pixels for letter A is due to increase in pixel density.
 
Please confirm.  Please also feel free to add this to your article (and edit for clarity).
 
Thanks,
Luke
 
PS:  I understand that the pixel density argument might lead to people into false thinking that DX sensor is better.  I'm just not sure how to really explain this crop sensor issue so there is no false understanding.
Hey Luke,
 
No worries about the delay. I am on your schedule!
 
Nice diagram! It looks accurate to me.
 
I believe I understand what you are saying and, yes, a lot of people, I believe, think that there is some sort of teleconverter or magnifying glass somewhere in the DX camera that causes that 300mm lens to look like a 450mm lens when it is actually a change of field of view created by a virtual cropping of an image. [Simplified terms.] 
 
So, your friend is technically wrong, but go easy on him! His logic is not uncommon as you can see in a myriad of the comments following the article. But, you are correct, there is no added optical magnification with a DX lens or DX camera—there is only a virtual magnification caused by the crop. You can tell him he is wrong, but buy him an adult beverage at the same time (if legal and appropriate) and go outside and take some photos and don’t worry about all the math!
 
Thanks,
 
Todd

Hello, thank you for the article. I have been shooting live band photos recently with my DX body Nikon D7200. With the low light and flashing stage lights I am having to shoot at relatively high ISO's above 3,200 upwards of 12,800. Another photographer shot the same show constantly at 1,600 ISO and higher shutter speeds than me with an FX Nikon D750. Does that mean that if we both have a 50 prime (or 35mm on mine to compensate for the 1.5x crop factor) that we would get different results in exposure with the same shutter, aperture and ISO? Considering changing to that camera but I like the extra "reach" with my zoom lenses.

Hey Jeffery,

Good question.

So, if he is shooting a 50mm f/1.8 lens at f/2 on the D750 at ISO1600 and you are shooting next to the other photographer with the D7200 with a 35mm f/1.8 lens at f/2 and ISO1600, you both should be getting virtually identical photos. They might get slightly better noise performance at a given ISO, but it shouldn't be very apparent as both cameras have sensors from the same generation of technology.

My guess is that the other photographer was shooting at wider apertures than you because exposure math remains constant regardless of the sensor size of the camera. If it didn't, light meters would have to have settings for cameras with different sized sensors.

Do you know what aperture they were working at? Let me know and thanks for your question!

PS. Sorry for the delay in replying...I was out of the office for the holiday.

Hi Todd,

This article has been very helpful to finally make up my mind to stick with Dx (Nikon D5300) and not to upgrade to Fx camera. I mostly shoot Landscapes and Travel photos and currently own Tokina 11-16, 35mm prime and 18-55 kit lens on my Nikon D5300 but I have been planning to add one more lens to my gear collection which can cover from wide to mid telephoto range since sometime i feel the need to zoom in and capture one part of the landscape and not the entire landscape especially when there is no interesting foreground and cases where I want to show the scale with telephotos. I have tried my hands on Tamron 70-300 for a month but i found it to be too long since it becomes around 110-450 on Dx and usually i dont prefer shooting landscapes in more than 200mm on Dx and with this lens i have also been losing 55-70mm focal range along with my other lenses. I am looking for a recommendation on wide to mid-telephoto range with VR/IS under 600 USD which can produce sharp images because i fell that my 18-55 doesnt give sharp enough images even when i think i am doing everything right.

P.S: I am also open for refurbished ones in good conditions.

Hey Naquib,

I am glad the article has been helpful to you!

Your Tokina and 35mm prime are great lenses. Nice work!

A couple of lenses come to mind for your telephoto dreams. One would be the venerable DX 18-200mm that falls just above your price range (well below if you go used). This would be a nice compliment to your existing kit and would replace your 18-55 easily. The 18-200 got rave reviews when it came out and has almost 1000 reviews on B&H at 4.5 stars. There is also a DX 18-300mm option as well. I would recommend doing your homework on both of those lenses, but I am sure you will find many happy owners. Both of those lenses should be sharper than your 18-55.

The DX 16-80mm is a fantastic lens, but a bit on the spendy side and probably isn't as long as you would like it to be.

Let me know if you have more questions and thanks for reading!

Hey Todd,

Your recommendation sounds really useful to me. but I have one more lens in my mind and that is Nikon 24-120mm. What is your opinion on this, i know this is a Fx lens?

Hey Naquib,

That is also a good lens...I guess I didn't think of that option! For some reason, maybe because I have never used that focal length zoom, those lenses rarely end up on my radar. Also, the Canon 24-105mm seems to have more of a following than the equivalent Nikon for some reason.

You'll have a little bit of a gap between 16mm and 24mm, but that isn't really a big deal. New, it is also well out of your specified price range, but we have a refurbished one listed for much less.

Thanks for the assist!

Hi Todd,

I have been thinking of buying a Nikon 24-120mm refurbished but delivery charges for india is quite significant, that's one issue for me.. and is there any import duty to be paid too on top of shipping charges from US to India?

Hey Naquib,

Sorry, friend! That is why outside of my wheelhouse. I recommend you go through the purchase process online and see if import taxes show on the web, or call B&H and talk to one of our sales team.

I wish I could be more help, but I honestly am not familiar with international shipping.

Hi! This has been a very helpful read and may be swaying me to stick with my D7200. I currently shoot indoors for hospital newborn sessions (Fresh 48) and In-Home lifestyle sessions. I'm using my Nikon 35 1.8 DX, so switching to full frame would also mean switching to new glass. I do feel limited in low-light situations and in tight spaces. I'm hoping to get into birth photography in the next year, so my current setup isn't going to cut it. I'm thinking of the Sigma 18-35, but I would really need to commit to sticking with the crop sensor to make that one worth it. I'm also considering the Sigma 24 1.4, with the idea that it could be used on my 7200 or on a full frame body if I ever do upgrade...which, again, I may not need to! Can you make a recommendation or do you have a better idea? Thanks so much! 

Hi Sarah,

Remember, you are shooting a great camera and using a great lens there. Beware of the gravitational pull of "newer" and "better" gear!

I like the idea of the Sigma 24mm prime. Why? You already said you are using the 35mm prime lens, so I sense you are not one to lean too heavily on the crutch of a zoom. Prime lenses, as you have discovered, are going to give you optimal image quality and, when it comes to that type of photography, I am sure parents are super picky about the images.

Future-proofing for a move to full-frame is a good idea, as well. And, not to push you off the fence, but if you did switch to full-frame, replacing your 35mm f/1.8 with a Nikon 50mm f/1.8 is not too much of a wallet drain...especially if you get the older AF-D version—an amazing lens on its own right.

Let me know if you have follow-up questions! I am glad the article was helpful. :) Thanks for stopping by!

Via email...

Message: Hi Todd,

I read your post on B&H and it was very useful - thanks for that.

However, I have one additional question. I am currently shooting with a D750 and a 24-70mm f2.8 lens. I am planning on using this lens on a D7200 which has a crop sensor (1.5x). When mounting the lens to the D7200, would it automatically become a slower lens, meaning that the photos taken at f2.8 would drop to an FX sensor equivalent of more like f4?

Two concrete examples:

1) I am shooting with the D750 and the above lens at f8 a lot when doing landscape photography to capture most of the scene sharp. Using the D7200, would f8 lead to the same result in sharpness or would I need to adjust the aperture?

2) In terms of brightness - I am usually shooting with the D750 at ISO 100 whenever possible. Shooting with the D7200 at f8 (as with the D750), would I need to increase the ISO in order to get the same level of light compared to the D750?

Thanks,

Rupert

Hi Rupert!
 
Thanks for the email!
 
Here we go!
 

However, I have one additional question. I am currently shooting with a D750 and a 24-70mm f2.8 lens. I am planning on using this lens on a D7200 which has a crop sensor (1.5x). When mounting the lens to the D7200, would it automatically become a slower lens, meaning that the photos taken at f2.8 would drop to an FX sensor equivalent of more like f4?

Nope. f/2.8 is f/2.8 when it comes to exposure. Mathematically, the DOF on the D7200 at f/2.8 will be closer to that of an f/4 lens, but the exposure does not change. If exposure changed, we would need to put in a crop sensor conversion to our handheld light meters.
 

Two concrete examples:

1) I am shooting with the D750 and the above lens at f8 a lot when doing landscape photography to capture most of the scene sharp. Using the D7200, would f8 lead to the same result in sharpness or would I need to adjust the aperture?

2) In terms of brightness - I am usually shooting with the D750 at ISO 100 whenever possible. Shooting with the D7200 at f8 (as with the D750), would I need to increase the ISO in order to get the same level of light compared to the D750?

 
Shoot at f/8 on both bodies for maximum sharpness. The sharpness of the image will be unchanged. Brightness is also unchanged. The same amount of light is coming through the lens at a given aperture…you are just capturing a smaller portion of that image circle with the crop lens. You will not have to change ISO.
 
I hope this clears things up, Rupert! Let me know if you have other questions and let me know!
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