zug55 Loc: Naivasha, Kenya, and Austin, Texas

I think that this post misses an important point. It only makes sense to use the crop mode if you are not using a full-frame lens. Of course you can shoot in crop mode, but the result would be no different from cropping in post, as dcampbell52 pointed out. Either way, you are losing part of your 24 MP your D750 delivers. Nothing is gained.

However, if you shoot your bird on a crop-sensor camera (like the D7000) but with a full-frame lens, you get the same cropping effect (i.e. better magnification), but you still are using the full sensor of your D7000, that is you get a cropped 24 MP image. So you get better image quality this way.

lamiaceae Loc: San Luis Obispo County, CA

Do I have to explain this? I don't even own a FF DSLR. OK, given you understand FF and CF sensors. Crop Mode on a FF camera (not just Nikon FF models) means when you put a (DX) lens on the camera that is meant for a FF body that does not throw a large enough image circle to cover the entire 24x36mm FF sensor, the camera (automatically) only uses the center of itself that is about the size of a APS-C sensor. This keeps from getting a round image like you might if you put a DX lens on a film Nikon camera, but the sensor is using far fewer pixels of course, so a 36MP FX camera shooting in Crop Mode would produce a DX sized image of only about 16MP. I believe Canon and Pentax also have Crop Mode on their Full Frame DSLRs as well.

ggenova64

My understanding of cropping is a full sensor goes back to shooting film days (“What’s That!”) replicating the 35mm film.
Gino

amfoto1 Loc: San Jose, Calif. USA

Unlike Canon full frame cameras, Nikon full frame (FX) cameras are able to use their DX (crop) lenses. When a DX lens is put on an FX body, the camera automatically switches to "DX crop mode" and only utilizes an APS-C size area of the image sensor (this may or may not be designated in the viewfinder, depending upon the model).

The Nikon FX camera user also has option to set the camera to DX crop mode even when FX lenses on it. However, it's the same as if they cropped the image that amount in post-processing.

Depending upon the resolution of the FX camera, a user may be giving up a lot if they use the DX mode of the camera. For example, when a 24MP D750 is used in DX mode, what remains will only be about 10MP. A 36MP D810 does better, with about 15MP images in DX mode. But in either case, it would be better to simply use a DX camera such as a D7200 with 24MP or a D500, D75000 with 21MP. On the other hand, a 46MP D850 (FX) will produce pretty respectable, approx. 20MP images in DX mode.

Canon full frame cameras do not have an "APS-C crop mode". In fact, Canon's "EF-S/APS-C crop" lenses have a modified mount designed to prevent them from even being mounted onto their full frame cameras.

Some Canon cameras do allow you to set a different aspect ratio.... Though it may be only in Live View or when recording Video. For example, the 5D Mark IV's native aspect ratio is 3:2... but it also can be set to 5:4, 16:9, 1:1. I wouldn't be surprised if some Nikon and others can do this, too. Aside from 3:2, these are crops, too, of course. But same as with FF/APS-C still photos, the same can be accomplished cropping the image back at your computer instead. (Video may be better shot in the aspect ratio.... I dunno because I don't shoot it.)

I have no idea about Pentax and Sony... whether their FF cameras have "crop mode" and aspect ratio option or not. I don't really care since it's not something I'd use in any case. (I'd just crop in my computer instead.)

All Olympus are micro Four/Thirds format now... no full frame models at all.

rts2568

Hi I'm Trying,

Markngolf mentioned the major deception of which manufacturers and the ignorant ply as fact, that a FX (full frame/35mm equivalent) lens of a particular focal length Somehow magically increases its focal length when used on a DX sensored body. If you believe in magic, then you are free to dream on!

A crop factor can be identified in two terminolgy characteristics.
1. it can be the term used to identify how a camera that has an FX sensor is in-camera changed to use the projected light coming in from the rear of your lens to only cover a DX sized area (18x24mm) in the center of the actual FX sensor (24x36mm). It's a crop factor because - in the context of Nikon, only half of the FX image will be actually seen fully on the sensor or in most cases, the viewfinder also, when dialling in Crop factor. In the same way, when a DX lens is used on an FX sensored camera, the in-camera 'DX crop' may only be allowed to see 1/2 the area of the FX sensor. In the old film days', cameras like the Olympus 1/2 frame cameras which used 35mm film but the lens was only designed to give enough light projection to produce 1/2 frame results - Olympus Pen cameras of the 1960s for instance.

2. The other use is to identify lenses that are designed to only project the DX (plus waste/vignettes etc) format. The main advantage for choosing these lenses is that they are much lighter, cheaper to buy, and only primarily designed to be used on a DX (D200/D300/D500)camera, in the Nikon range, they have designed their bodies and lenses to fit both DX & FX bodies to be interchangeable, either lens fits both bodies. Makes like Canon only do this in a very limiting and inconvenient way, other makes don't allow either. Some other makes allow limited exchanged including those that can be exchanged when an adapter is used ( all of which are limiting - focal lengths are always altered, minimal focus points becomes shorter and other problems).

In short, when using an FX lens on a DX sized body, only half of the projected image is recorded; NOT doubled in the subject size as is suggested in too much of the irresponsible rumour mongering that still floods the airways. In the case of photographing a bird for example, when taken with an FX lens, the outer areas of the projected image is 'cropped' to fit onto the Smaller DX sensor; not enlarged as if the lens suddenly becomes 1.5 times longer in focal length (i.e. 1.5 x crop factor.) the bird is the same size on the sensor capture with either a DX or FX sensor on board. If you have an FX Nikon body you will have the option of only showing you the DX sensors' area that is captured/cropped from the lenses projection.

If someone tries to convince you that the crop factor means that a 200mm lens becomes a 300mm focal length when fitted on a DX body- don't believe them. This fallacy has been going on far too long.

The truth is that a DX lens only projects half the subject area that an FX lens would capture.

Points to keep in mind:
An FX lens on a DX body does not miraculously become a focal length 1.5x longer when used on a DX body!

This is basic stuff, it is too easy to fall into the trap of being led to believe that if you buy a DX body, you have subject magnification when using an FX lens, a pretend fact that you don't actually have. All you have is that the actual FX subject is CROPPED(!) - it isn't, when used on the DX camera - the top, both sides and the bottom of the FX subject is simply cropped off, like cutting a paper photo with a pair of scissors - cut off all outer edges and you will find yourself with a DX 'crop mode'.

Hope this helps and don't feel bad about not understanding this conceptual problem, both experienced amateurs and I'm very sad to say are supposedly professional photographers too still don't know the reality of this.

Ron

bpulv Loc: Buena Park, CA

I have both a Nikon D90, a crop frame (DX) camera, and a Nikon D800 (full frame FX) that I bought a few years later. Almost all Nikon lenses are backward compatible; i.e., lenses for the original Nikon F from 1952 will work on the newest models as a manual lens. To maintain that compatibility, Nikon FX cameras automatically recognize when a DX lens is attached and, although the lens only illuminates a portion of the full frame sensor, the view finder and live view LCD display shows the picture full size. Because the DX lens on a D800 uses only a portion of the sensor, it provides an image that occupies about 17 megapixels as compared to 36.6 megapixels for an FX lens. Since my D90 is a 12 megapixel camera, I gain resolution when I use them on the FX camera. You should note that Canon cameras are not fully backward compatible to the extent that Nikon has maintained its compatibility with older equipment through the years.

zug55 Loc: Naivasha, Kenya, and Austin, Texas

Ron's lengthy post show how complex this issue is. And of course he is right that a 300mm lens always will be a 300mm lens, regardless of whether it is a DX or FX lens or if you use it on a DX or FX body. Focal length is defined by the optical properties of the lens. As Ron pointed out, many manufacturers and dealers create false claims, such as that this lens has a 450mm 35mm equivalent. I agree with Ron that this is bogus. It still is a 300mm lens optically.

So I agree with Ron that this is all about cropping--and about field of view. A DX camera with 300mm lens gives you a narrower field of view than a FX camera with a 300mm lens because it has a smaller sensor. So the bird shot with a DX camera will appear larger than the bird shot with an FX camera. We call this the crop factor. So if you want your FX bird to have the same size as your DX bird you have to crop the image.

Here is the point I was trying to make before. Both D750 (FX) and D7000 (DX) have a 24 MP sensor. In the example above, your DX bird image has 24 MP. Your cropped FX image has about 15 MP. Thus your DX image in this case has a higher image quality than your FX image.

billnikon Loc: Pennsylvania/Ohio/Florida/Maui/Oregon/Vermont

In Canon, a cropped sensor camera is the 7D Mark II. Canon also makes full framed cameras. Nikon also makes cropped sensor cameras, D500, D7500, D5000 and D3000 series cameras. The D850, D810, D750, D610, and D4, D4s, and D5 are all full frame cameras. Conon crop cameras have a 1.6 factor and Nikon has a 1.5 factor. ie. A 300 mm 2.8 lenses on a full frame camera stays st 300 mm. If you put that lens on a cropped sensor camera like the D500 you multiply the crop factor of 1.5. So 1.5 × 300 = 450. Now it has an effective perspective of 450 mm lens, it is not a 450 mm lens, but has an equivalent focal length of 450 mm. Hope this helps.

bpulv Loc: Buena Park, CA

You have all missed the point of the original question completely. He is NOT talking about using an FX lens on a DX camera, he wants to use a DX lens on a FX camera. THERE IS NO CROP FACTOR INVOLVED! An FX camera does not "crop" the image of a DX lens. It uses an area of the sensor equal to the size of a DX sensor to produce the same AOV image that the DX lens has on a DX camera body.

CatMarley Loc: North Carolina

It limits the size of the image on the sensor to that of a crop size sensor, so that you can use your crop series lenses on your full frame camera body.

olemikey Loc: 6 mile creek, Spacecoast Florida

Dang, beat my Sony's by .1 !!!!! I want another FF, but for now I enjoy the "crop sensor" 1.5X I get out of all my old glass. Only downside for me is it makes wide lens choices that much tougher.

Mark, most times KISS beats technical explanations by a mile, unless you are talking to SME/Scientist/Engineers....good answer!!

via the lens Loc: Northern California, near Yosemite NP

From your perspective it is "not advisable" to use a full frame camera in cropped sensor mode: why not? I've done this often without any resultant quality problem with the image or a print, but I have not done so specifically using a DX lens, only a lens designed for a full-frame camera. So curious about your comment.

zug55 Loc: Naivasha, Kenya, and Austin, Texas

Why? It only makes sense if you have have a DX lens. By doing so you are throwing away megapixels. Why would you automatically crop every picture you take? It is like having a sporty car with a 5-speed transmission, but you never use fifth gear. Cropping in post sometimes makes sense to create the image you want. But I do not see the reason for cropping every picture you take. Why not adjust with your zoom lens or get closer to get the shot you want?

via the lens Loc: Northern California, near Yosemite NP

You say:

This is basic stuff, it is too easy to fall into the trap of being led to believe that if you buy a DX body, you have subject magnification when using an FX lens, a pretend fact that you don't actually have. All you have is that the actual FX subject is CROPPED(!) - it isn't, when used on the DX camera - the top, both sides and the bottom of the FX subject is simply cropped off, like cutting a paper photo with a pair of scissors - cut off all outer edges and you will find yourself with a DX 'crop mode'.

And I don't have a problem with what you are saying.

However, does this not mean that using my D500 (cropped camera) (rather than my D800-full frame camera) I get a larger subject in the camera without having to crop after the fact, which would mean I would then cut out megapixels. So, if I use my D800 in a crop mode, which does mean fewer megapixels as set by the camera manufacturer for that size image, I get the subject closer (already cropped) and then can use all of the allocated megapixels for that image to print in a 1:1 ratio. I'm too lazy to run this test and you might have already done it. And, in the end, I do seem to be actually seeing the subject magnified so aren't I getting "subject magnification"? I'm always curious about this so just wondering about your take on this.

Chris T Loc: from England across the pond to New England

Zug ... the Nikon D7000 has a 16MP sensor. The D7200, D7100, D5600, D5500, D5300, D3400, D3300, D3200 are all DX (Crop Sensor) cams w/ 24MP ...