DX Lens on an FX body

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Dinsdale

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I'm fully aware of the "lazy photgraphers" thread on these forums and would have read up on the matter myself first, but this question is very specific and in depth. So apologies to the "lazy photographers" thread OP.

Right, here goes...

I have a Nikon D300S my good lady brought me as an xmas present. At the time I had a D80 with 18-135 kit lens and 70-300 non VR. I had the choice of D700 or D300S, my preferrence was for the D700 but it's a full frame camera and my DX lenses I knew would reduce the 12 megapixels down to about 5½ megapixels. So it was have a really nice camera running at reduced capacity or have a good camera running as it should. I chose the D300S (obviously) and have since added further DX lenses to the kit.
My questions are:

1) I know the focal length of a lens on a crop body is longer 35mm equivalent, am I right in thinking that they become correct on an FX body? i.e. 35mm becomes near to 50mm on a crop body but stays at 35mm on an FX body?

2) The FX is a much better sensor, I've read, because the pixels are bigger than in the DX sensor for the same resolution. As a result the IQ is so much better on the FX camera. If I used a DX lens on the FX body the resolution drops by about half, but does the IQ reduce too? If so, is it by so much that it would mean either putting up with really substandard stuff or replacing my DX lenses? Would I still get that lovely full frame IQ using a DX lens on an FX body? If the IQ is reduced would it still be better than on the D300S?

Reason I'm asking is we were looking in Jessops last night at a D700. I said that I'd wished I went for the D700 instead of the D300S. My wife asked if my lenses would fit the D700 I said yes but with certain drawbacks, which she wouldn't have understood but accepted my reasoning. She then went very thoughtful in a way that I've seen before, if you catch my drift (he says fingers doubly crossed). :D

I'd really appreciate your thoughts on this matter please.

Many ta's in advance. :thumbs:
 
A) only a few DX lenses can work fairly well on FX. One such example is Tokina 12-24mm from 18mm onwards. The rest is waste of time and money.

B) You will need very good glass fro D700. If money is an issue, get a few primes like 35/2, 50/1.4 and 85/1.8. Cheap zoom on the pro body is a really bad thing to do.

C) What exactly is D300s lacking for your needs that D700 would do?

D) Why wouldn't you invest in good glass instead? Usually they have f/2.8 or lower somewhere in the name... There is no point in having D700 if you can't use it properly.

E) To be honest, these lenses are hardly suitable even for D300s or a cheaper DX body. Get good ones.
 
Without opening a debate of DX vs FX... here's a VERY short answer

1) 35mm is 35mm on any body, the FOV however changes so the subject appears closer to you on a crop body.

2) Better... well yes in some cases, but to be honest a D300s is one hell of a DX body.

Don't get too hung up on FX bodies. Build up your FX compatible lens collection first (which of course are equally good on a DX body). You will happily fork out over £1000 on all new FX lenses so build up your glass first is my advice. The D300s will sell well s/h in the future.
 
Dinsdale said:
1) I know the focal length of a lens on a crop body is longer 35mm equivalent, am I right in thinking that they become correct on an FX body? i.e. 35mm becomes near to 50mm on a crop body but stays at 35mm on an FX body?
Click to expand...
Right... Prepare to do some mental gymnastics...

A 35mm lens is a 35mm lens whether it is on a full frame or crop body. Assuming a perfect lens that can illuminate any size sensor, all the different sized sensor does is give you a smaller or larger field of view. The bigger the sensor, the bigger the field of view. When people talk about equivalence, it is this that they mean. To get the same field of view as a 50mm on a full frame, you need a 35mm on Nikon 1.5x crop. So... in your case, putting a 35mm on a crop will give you the equivalent of a 50mm on a full frame.

However, when you put your DX lenses on an FX body, the camera automatically crops to crop sensor size, so you'll get exactly the same field of view as on the D300S.

As another poster has said, get good glass first. The D300S is a pretty capable camera (allegedly, as I'm a Canon user...)
 
daugirdas said:
A) only a few DX lenses can work fairly well on FX. One such example is Tokina 12-24mm from 18mm onwards. The rest is waste of time and money.

B) You will need very good glass fro D700. If money is an issue, get a few primes like 35/2, 50/1.4 and 85/1.8. Cheap zoom on the pro body is a really bad thing to do.

C) What exactly is D300s lacking for your needs that D700 would do?

D) Why wouldn't you invest in good glass instead? Usually they have f/2.8 or lower somewhere in the name... There is no point in having D700 if you can't use it properly.

E) To be honest, these lenses are hardly suitable even for D300s or a cheaper DX body. Get good ones.
Click to expand...

A) Yes, because of the restriction of the corners.
B) Yes it helps but even those primes are going to cost the best part of £550 unless you go for manual lenses.
C) The D700 is just so much better.
D) There's no point in having ANY camera if you can't use it properly. Unless you mean that if you use 'inferior' lenses then you're not using it properly.
E) I disagree.

OP

1) Yes and no. The 18-135 being DX will use the 'cut down' sensor so will still have the 1.5 applied. The 70-300 I believe is an FX lens so will fill the full frame and be true 70-300. I think that's correct.
2) I'm no expert but I would figure that the IQ wouldn't drop per se on the camera sine the size of the pixels remains the same, just fewer of them. The 'inferior' glass MAY make a difference.

If you get one, consider the Tamron 28-75 f2.8 lens. Very pleased with mine
 
Hi - you haven't said what you use the camera for...FX has it's advantages in low-light situations and lots of wedding & sports pros use them because of that...but for wildlife you lose that 1.6 efffective extra magnification which a crop sensor body gives you (what I mean is a zoom lens will reach "further" on the D300s than the D700).

It's true that to really appreciate the D700 you should get a matching quality lens (I have the 24-70mm f/2.8) but I disagree with the earlier post of
Cheap zoom on the pro body is a really bad thing to do
Click to expand...
unless there's a technical reason I'm not aware of...for example - the image below was taken last week with a £1600 D700 body and a £130 Sigma 70-300mm zoom at a decent distance (220mm then cropped in LR, click the image to view large)... With the less-expensive lenses good light is your friend :)

 
This is the sort of vignetting you can expect from a Sigma 10-20 on a D700.
4050193432_c3c925124a.jpg

and
4050193420_526824ab9e.jpg


I think the area you could crop to is larger than the size the D700 would automatically crop it to in its Dx mode but it still crops out some of that lovely Fx width.
 
I feel very well versed on this as I have had a similar problem.
I brought a D700 and a D300s as a back with the thought of having the D300s with a tele lens on permanently.

To cut a long story short I realised I loved full frame so much that I even found myself taking the tele lens off the D300s so I could attach it to the D700.
Obviously this was just my preference and I am not saying the D300s is not a good camera as it is fantastic; I just seem to feel more at home with FF.

So I sold my D300s and set about looking for another D700 and as we speak I have sat on my desk a totally new Nikon 18-200 VR MKII lens.

Would I use this on my full frame, NO
So I will be advertising it over the weekend to trade for something I can use on the D700 and is a FX rather than DX lens.
I don’t see the point in using a FF body in reduced mode as it does not make the most of the camera and a D300s would probably produce better images anyway.

My advice to you would be if you don’t need FF and you have a set up around a DX body then stay with the D300s.
If however you have been bitten by the full frame bug then beware it gets very expensive but if you are like me you will drool over the results.
 
Many thanks for the replies guys. :thumbs:

In trying to reply to them as a whole...

I am an amateur desperately trying to get consistently chrystal clear shots, with good use of DOF that really "pop". I'll shoot anything that's not illegal, immoral or a wedding, but prefer motor sports, nature and landscapes mainly. I'm also a bit of a purist, what comes out of the camera should be the end result. All this masking, burning, dodging, heavy pp'ing etc. turns it into an artform rather than photography.
Don't get me wrong some brilliant picutres have been created that way but photography in my mind is about capturing the image as you saw it at that moment in time. If you want to "create" an image by all means do so but that's when it stops being a "photograph" to me.

Why do I want a D700? Always buy the best you can afford. In my opinion, limited as it is, the D700 is better than the D300S and we've all read why. I'm very much aware that an expensive camera doesn't necessarily mean great photos and that it takes years of practice, experience and learning the skills. But having the best tool for the job sure helps.

... and anyway, why not? If I offered you a Jaguar would you turn it down for a Mini?

I totally agree having top quality "glass" is a must too. Yes, two of my current lenses aren't anything near good quality - well they're better than Canon ones :naughty: - and I'd need to upgrade them certainly. My dream is to get a Nikkor 300mm F/2.8 VR but at £3½K as shot that's a long way off.

As for focal length I understand the maths etc. now thanks. However, I'd sooner have the better image quality over focal reach anyday.

As for make of lens, the purist in me wants to try and keep to Nikon ones. I'm aware that there's probably just as good quality elsewhere but...

Once again many thanks for the great advice it's all a lot more clear to me now and given me food for thought. :thumbs::thumbs:
 
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