Nikon FX lenses on DX bodies.

Orangecroc

Orangecroc

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I'm aware that FX lenses work with DX bodies, I was just wondering about a few different things. Will they be sharper than the DX equivalents towards the edges because the light hitting the DX sensors will be more from the centre of the lens than the edges?
How much of an effect do they have on balance when attached to the body?
 
Hummm, would that mean on a FF we would overexpose the centre of the frame more than the edges? I guess having two DX and two FX lenses I will not lose too much sleep over this but interesting to see what comes out :)
 
TLR-330 said:
Hummm, would that mean on a FF we would overexpose the centre of the frame more than the edges? I guess having two DX and two FX lenses I will not lose too much sleep over this but interesting to see what comes out :)
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I don't think it would do that to exposure, I meant because the angle of incident leaves means the smaller sensor collects the light projected from the centre and the FF sensor collects light from the whole lens. I am asking because I don't know if this is the case but thought it may be thinking in terms of the same principle that causes vignetting on FF using DX lenses.
 
In theory if the lenses are built to the same specification then centre sharpness should be the same. However, I'd assume edge to edge sharpness using the FX lens would be better as you're losing the outer edges of the image circle.

However, not all lenses are created equal and most of the pro/high end lenses are FF so you'd expect these to perform better anyway. It has to be taken with a pinch of salt to a degree but DXO allow you to marry different bodies to different lenses to see what the sharpness is if the lens/camera combo.

As for balance, it will depend on size and weight of both camera and lens, obviously the bigger and heavier the lens the more front heavy it will feel.
 
snerkler said:
In theory if the lenses are built to the same specification then centre sharpness should be the same. However, I'd assume edge to edge sharpness using the FX lens would be better as you're losing the outer edges of the image circle.

However, not all lenses are created equal and most of the pro/high end lenses are FF so you'd expect these to perform better anyway. It has to be taken with a pinch of salt to a degree but DXO allow you to marry different bodies to different lenses to see what the sharpness is if the lens/camera combo.

As for balance, it will depend on size and weight of both camera and lens, obviously the bigger and heavier the lens the more front heavy it will feel.
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Thank you, that's what I thought.
 
Orangecroc said:
I don't think it would do that to exposure, I meant because the angle of incident leaves means the smaller sensor collects the light projected from the centre and the FF sensor collects light from the whole lens. I am asking because I don't know if this is the case but thought it may be thinking in terms of the same principle that causes vignetting on FF using DX lenses.
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The whole lens contributes to each part of the image. If you use a DX sensor with a FX lens, you are only using the centre of the image circle but that centre is formed by the whole lens.

You cannot map the image to a part of the lens - centre of image does not equate to centre of lens and edge of image does not equate to the edge of the lens.
 
It's actually quite a complicated question, though there are a couple of broad generalisations. It is 'easier' to make a lens to cover a smaller format, but the designer may choose to excercise that freedom in different ways. Could be sharper, could be smaller/lighter, could be cheaper, have a greater zoom range, a wider aperture etc. The format benefits diminish as focal length increases, which is why EF-S and DX lenses tend not to stray much above 50mm (at least at the wider end).

It's also true that if you put the same FF lens on a crop-sensor body, it will appear slightly less sharp because the smaller format demands more resolution, therefore contrast goes down (basic MTF theory) and perceived sharpness with it.

It's often said that buying FF lenses for cropper is a win-win for when you want to move to FF and use the same lenses. IMO it's actually a loose-loose, because you'll not benefit from the format advantages, while paying for FF coverage that you can't use. Then if you do change to a FF camera, the effective focal lengths change significantly so you'll want to get a new set of lenses anyway.
 
I will counter that viewpoint slightly with a couple of points:

FF lenses don't have to magnify so much so don't actually need to work so hard to produce a sharper image so some (particularly crappy) FF lenses are worse on DX bodies than on FF.

Yes an FX lens on a DX body means that you are only using the better part of the lens to resolve the image. However, designing and making smaller lenses is easier that big lenses since the advent of good lens CAD so a specific DX lens could quite probably work just as well as an FX lens on a DX body.

All I'm saying is that there is no easy and 100% correct generalisation.

To poke fun I would suggest it derives from Canon shooters, for which all the coveted L-Glass is Full Frame and is therefore the be-all and end-all.

edit: too slow :)
 
HoppyUK said:
It's often said that buying FF lenses for cropper is a win-win for when you want to move to FF and use the same lenses. IMO it's actually a loose-loose, because you'll not benefit from the format advantages, while paying for FF coverage that you can't use. Then if you do change to a FF camera, the effective focal lengths change significantly so you'll want to get a new set of lenses anyway.
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Yes the effective focal length would change but it still completes a range. I got a 70-300 and 150-600 on FX but a DX camera. Even if I had a FF camera they would make little difference as to I don't see anything much else (unless I start looking at f2.8). But if I was to buy another camera (no GAS syndrome at this point) it would be a full frame for having had one.
 
TLR-330 said:
Yes the effective focal length would change but it still completes a range. I got a 70-300 and 150-600 on FX but a DX camera. Even if I had a FF camera they would make little difference as to I don't see anything much else (unless I start looking at f2.8). But if I was to buy another camera (no GAS syndrome at this point) it would be a full frame for having had one.
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The benefits of the smaller format are really at shorter focal lengths. Eg, a popular 'standard zoom' on a crop format Canon is the EF 17-40/4 (complete with its red L ring ;)). But it can't hold a candle to excellent EF-S options like the 15-85 IS with masses more range and image stabilisation, or the 17-55/2.8 IS with both more range and faster aperture. Then when it's time for full-frame, the 17-40L reverts to being the super-wide it was always designed to be, and you need to buy another FF standard zoom like 24-70.

So you don't get the most out of the crop format camera, and have to buy new FF lenses anyway.
 
HoppyUK said:
So you don't get the most out of the crop format camera, and have to buy new FF lenses anyway.
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My retail therapy (GAS to the locals) is accompanied by retention therapy. The crop sensor camera will be kept for the wide lenses ;-)
 
TLR-330 said:
My retail therapy (GAS to the locals) is accompanied by retention therapy. The crop sensor camera will be kept for the wide lenses ;-)
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Didn't you mean the longer lenses??? Or is the product of your mind too subtle for me to understand?
 
droj said:
Didn't you mean the longer lenses??? Or is the product of your mind too subtle for me to understand?
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My DX lenses are the wider/widest lenses I got. My longer lenses are the full frame ones. Clearer?:)
 
Orangecroc said:
I'm aware that FX lenses work with DX bodies, I was just wondering about a few different things. Will they be sharper than the DX equivalents towards the edges because the light hitting the DX sensors will be more from the centre of the lens than the edges?
How much of an effect do they have on balance when attached to the body?
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I've often wondered why anyone should worry so much about edge sharpness - I mean who amongst us actually requires such clinical perfection in our photographs?

The balance, as said above, is individual to body and lens (well ain't it obvious?). And, for all I know, whether you're left or right-handed and the shape of your hands. So let's just retire the question.
 
TLR-330 said:
My DX lenses are the wider/widest lenses I got. My longer lenses are the full frame ones. Clearer?:)
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I'm so slow on the uptake (sigh). Thank-you, Charles. So despite your tlr-330 moniker, you have digital equipment? Shocking business!
 
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droj said:
I've often wondered why anyone should worry so much about edge sharpness - I mean who amongst us actually requires such clinical perfection in our photographs?

The balance, as said above, is individual to body and lens (well ain't it obvious?). And, for all I know, whether you're left or right-handed and the shape of your hands. So let's just retire the question.
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I think it's a fair question. People like lenses with edge to edge sharpness, and isn't this what all lens manufacturers are striving for? I recently shot a holiday photo of my wife at the base of some church steps and deliberately set her over to one side but unfortunately she looks a tad distorted due to being close to a corner of the frame. Far from ideal.
 
snerkler said:
I think it's a fair question. People like lenses with edge to edge sharpness, and isn't this what all lens manufacturers are striving for? I recently shot a holiday photo of my wife at the base of some church steps and deliberately set her over to one side but unfortunately she looks a tad distorted due to being close to a corner of the frame. Far from ideal.
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Hang on a min, distortion & sharpness are different things ...
 
droj said:
I've often wondered why anyone should worry so much about edge sharpness - I mean who amongst us actually requires such clinical perfection in our photographs? <snip>
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Lots of people. Landscape and architecture are particularly critical for edge sharpness. For most other things it's very desirable too.

Orangecroc said:
They are, but distortion affects sharpness when corrected.
I was asking with the intention of learning more. The more information I can garner from specific questions, the more I will be able to rely on my own knowledge in the future.
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Not really, not to the minor extent of distortion correction in normal context.
 
HoppyUK said:
Lots of people. Landscape and architecture are particularly critical for edge sharpness. For most other things it's very desirable too.



Not really, not to the minor extent of distortion correction in normal context.
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Maybe we all pixel peep too much. Maybe it's better to sometimes look at the picture as a more normal person would :D

And on the issue of FF and APS-C and sharpness and lenses...

I suppose we can only really judge each individual lens on its own merit. As APS-C pictures need to be magnified more for any given picture size they will suffer for that at least to a degree and to counteract this (again at least to a degree) the lenses for the smaller system should be designed for that smaller system and designed to be sharper so that the final more magnified picture retains more sharpness in its final form :D

One thing I've noticed using old film era lenses on my MFT and FF cameras is that they appear to be very sharp on my FF camera and much less so on my MFT cameras. In fact I'd say that the sharpness they produce at least in the centre of the frame with my FF camera is possibly better than some of my nice primes manage on my MFT cameras. As my old film era lenses are pretty ho hum by todays standards I'd guess that this shows the effect of magnification on sharpness and the need to use sharp lenses on smaller formats to try to mitigate this.

This is one reason why it's maybe best to use lenses designed for your camera rather than lenses designed for another camera which conveniently fit yours, especially if your camera is one with a smaller chip in it and the lens you're using was designed for a camera with a larger chip on which it wouldn't need to work so hard.
 
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woof woof said:
Maybe we all pixel peep too much. Maybe it's better to sometimes look at the picture as a more normal person would :D <snip>
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Well yes, we do pixel peep too much, and Droj makes a good point (in his usual style :)) but when buying lenses, who can say that we're never going to want a nice landscape crisp to the edges, or a shot of a cathedral full of intricate detail, or just a group shot at a wedding with faces clear and sharp right across? I could also add that maybe Droj should consider not putting the main subject right in the middle every time ;)
 
I use three FF lenses, the 24-70 f2.8, 70-200 f2.8 and the 200-500 f5.6, on a D500 (DX) and a D810 (FF). To be honest I noticed very little difference, if any, in images taken on either camera. Technically, I suppose, there may be some difference, I just haven't noticed it.
 
droj said:
Hang on a min, distortion & sharpness are different things ...
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True, I should have worded it better. But my point still stands that if you eliminate the edge distortion edge to edge image quality will better. Some perceive this distortion as lack of sharpness though.
 
With only 1 exception, all the lenses I've used on the Dx bodies I've owned have been FF compatible. Mainly because I continued to use film alongside digital for wide angle and wanted to be able to use all the lenses on all the bodies. The exception was the kit 18-70 which came with the D70 many years ago - punched so far above its weight/cost that I was reluctant to let it go (but did, as a sweetener for a D200 sale). I do have an 18-200 Dx but that's for the V1!
 
HoppyUK said:
Well yes, we do pixel peep too much, and Droj makes a good point (in his usual style :)) but when buying lenses, who can say that we're never going to want a nice landscape crisp to the edges, or a shot of a cathedral full of intricate detail, or just a group shot at a wedding with faces clear and sharp right across? I could also add that maybe Droj should consider not putting the main subject right in the middle every time ;)
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I'm as guilty as anyone but I'm trying to behave more normally. I recently took a shot with my old Minolta Rokkor 35mm f1.8 and I've decided that it's perfectly acceptable edge to edge, and that's a decades old lens so I'm sure that more modern stuff is easily capable.
 
What did you do with the film? Scanned it so you added a nice bit of blur all across? (No reason why an old lens should not be even in its resolution).
 
TLR-330 said:
What did you do with the film? Scanned it so you added a nice bit of blur all across? (No reason why an old lens should not be even in its resolution).
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How odd. Did you do that?

I'm reasonably sure that these old lenses can't compete on a test bench with modern lenses but they're still capable but maybe not so sharp that people need to do anything that drastic. My point was that even old and by todays standards relatively humble lenses are still quite capable so todays will be more than capable and shouldn't have to worry about sharpness.

That was my point.

But I'm wishing I hadn't bothered :D
 
You already are using an FX lens on a DX body. Did you realise the 50mm 1.8G you own is an FX lens and you have a DX body. I used that lens on a d700 and now d600, both FX bodies and it works amazingly.
 
GTG said:
You already are using an FX lens on a DX body. Did you realise the 50mm 1.8G you own is an FX lens and you have a DX body. I used that lens on a d700 and now d600, both FX bodies and it works amazingly.
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Yeah, I knew this, which is why I was asking the question, because it as exceptionally sharp lens despite its affordable price tag.
 
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