Comments on: FX (Full frame) vs DX (Crop frame)

By: andrew

andrew — Wed, 04 Nov 2009 19:32:45 +0000

Yes, when you use DX camera you loose approximaly 1 stop in terms of aperture – e.g. light wise and Deapth of Field wise.
So, your typical 2.8 FX lens like 24-70 or 70-200 behaves more like 1.8 on FX vs 2.8 DX lens on DX camera.
Let’s say you have 24-70 2.8 on FX camera vs. 17-55 2.8 ( DX lens on DX camera ) , all other differences aside , 24-70 will be 1 stop superior.

I would also add that, at least with Nikon ( I am not familiar with other brands ) you get a slightly wider perspective with full frame – 14 mm lens on FX is wider than 10 on DX. ( effectively 15 mm – and by the way , 1 mm difference is noticeable at this focal length)

By: ben

ben — Sun, 18 Oct 2009 10:36:20 +0000

I wouldnt have thought it would make any difference. Imagine (god forbid) reducing the size of an FX sensor by putting black paint on it, the light falling on the remaining part of the sensor hasnt been affected has it? Therefore it should remain as bright as before. I could be wrong, but thats just how I see it.

By: admin

admin — Thu, 10 Sep 2009 06:10:53 +0000

Interesting question, but I have no answer to that

By: Bill Young

Bill Young — Mon, 17 Aug 2009 17:13:05 +0000

OK, I have done some sums to answer a question no-one seems to ask. The question is, ‘don’t I lose light when using an fx lens on a dx camera?’ After all, when the fx lens is focused on the same sensor it is spilling light. Everybody (including Ken Rockwell) says there is optically no difference but I don’t understand. .
The sensor in the canon dx body is 38% of the size of the sensor in the fx body – the square of 1/1.6 – so is losing 62% of the light from the fx lens. That’s more than a full stop. The f4 lens becomes slower than an F5.6!

By: admin

admin — Thu, 30 Jul 2009 18:43:48 +0000

Might be not a good idea, most of those legacy / old lenses are discontinued. Because of it, you won’t able to find a new one. You can search for used one but no guarantee about the performance and condition.

Unless you have the legacy lenses on the first place, I don’t think it will worth investing on it.

By: Bill Young

Bill Young — Thu, 30 Jul 2009 16:03:55 +0000

A thought…
Is it worth investing in a full-frame in order to be able to buy and use great-value, high quality lenses designed for 35mm film cameras?