EF lens on a EFS body ( canon 600D) pros and cons ?

Orange_crunch · 9 Jul 2013

Is there any reason not to use a EF fit lens on a EFS fit camera ( Canon 600D )?
There is a Sigma DC Macro 17-70mm f/2.8-4.5 for sale ( £99) in a local trade in centre. Reviews on the net seem to be hit or miss... does anyone own this lens ?

Any info on a equivalent lens to buy would also be helpful

wyx087 · 9 Jul 2013

Sigma DC lenses mean for crop sensor (EF-S), Sigma DG are for full frame.

for your question:
pro: usually better image quality because crop camera only uses centre part of the projected image.
con: weight and size

MatBin · 9 Jul 2013

Only down side is size, ef-s lens can be smaller so FF are heavier/bigger (too slow typing, see above). Be aware Sigma lenses dont
always work on Canon bodies, they are reverse engineered to work on the current bodies when they (the lenses) are brought out. Eventually Canon bring out new bodies which may not then communicate properly with the 'old' Sigma lens. Canon's own kit lens of approxiamately the same focal length in ef-s fitting(non IS) has had mixed reviews as its a bit plastic and not terribly well built but image quality can be quite good. I believe the IS version is much better and good value second hand. They also do an expensive one.
Sorry forget just now which focal lengths are the better ones and which are the lesser ones, they overlap a bit at the wide end, in the Canon range.

Typically http://www.talkphotography.co.uk/forums/showthread.php?t=492433

Matt

Anorakus · 9 Jul 2013

Technically there's no reason why you shouldn't use an EF lens on a crop body. The only argument against it is in terms of excessive weight and price - since the sensor will only be using the central portion of the lens, the glass at the edges is unused. You're paying for it (especially so in the case of a L lens) and having to lug it around

EF-S lenses are designed for the smaller sensor and are made smaller and lighter.

A.

hollis_f · 9 Jul 2013

Orange_crunch said:
Is there any reason not to use a EF fit lens on a EFS fit camera ( Canon 600D )?

None at all. Use whatever lens is right for the job.

HoppyUK · 9 Jul 2013

wuyanxu said:
Sigma DC lenses mean for crop sensor (EF-S), Sigma DG are for full frame.

Yes.

for your question:
pro: usually better image quality because crop camera only uses centre part of the projected image.
con: weight and size

Not true on the IQ part. A FF lens on a crop format camera will always perform worse in the centre, because of the greater resolution required by the smaller format. Edge performance varies, because the edge of crop format is nearer to the centre and therefore sharper, set against the higher resolution requirement again. Usually, FF wins.

postcardcv · 9 Jul 2013

HoppyUK said:
Not true on the IQ part. A FF lens on a crop format camera will always perform worse in the centre, because of the greater resolution required by the smaller format. Edge performance varies, because the edge of crop format is nearer to the centre and therefore sharper, set against the higher resolution requirement again. Usually, FF wins.

So are you saying that the EF-S lenses are sharper than EF ones of the same focal length?

Petri · 9 Jul 2013

The 600D is an EF mount camera as much as it is an "EFS body" - it's designed to accept EF lenses and there's no reason why you shouldn't use them. Specific individual lenses may have strengths and weaknesses on a crop body, but there's no general rule either way as far as I know.

EFS lenses tend to be cheaper because they only have to cover the smaller image circle of a crop sensor and are therefore easier/cheaper to produce. They'd be rubbish on a full frame camera (if they fitted) but the reverse isn't true - far from it.

HoppyUK · 10 Jul 2013

postcardcv said:
So are you saying that the EF-S lenses are sharper than EF ones of the same focal length?

No, I wasn't making that point, rather saying that if you put the same lens on a smaller sensor, then (for the same sized final image output) you're asking it to deliver more resolution - by the crop factor, eg 24-lpmm on FF becomes vs 38-lpmm on APS-C 1.6x. When resolution goes up, contrast goes down which is the main reason why full-frame images are sharper. That's basic optical MTF theory, and it's got very little to do with pixels, within reason.

But since you mention it, a lot of lenses designed for smaller formats (APS-C, M4/3rds etc) are indeed sharper than FF lenses of similar focal length. There are three main optical design requirements that are in conflict - wide zoom range, low f/numbers, and format coverage (plus size/weight and cost). Reduce any of those things and you can have a sharper lens.