Beginner Difference between lengths for EF and EF-S

chelleon

chelleon

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Grant Vallely
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Hi all,

I can't seem to find the right or any answer... hopefully someone can help me out.

Have a 700D crop sensor and I know for instance that say a 24mm EF lens will be about 1.6 times length e.g. 40mm+ which is all fine and dandy.

BUT is the focal length of an EF-S lens as it is stated.. I.e EF-S 50mm... Is this actually the same 'view length' as you would see if you were to use an EF 50mm on a FF and EF-S 50mm on a crop (700D)

Or am I just trying to confuse myself..

I am looking at new lenses, and this is a stumbling block as to which I go for...
 
chelleon said:
Is this actually the same 'view length' as you would see if you were to use an EF 50mm on a FF and EF-S 50mm on a crop (700D)
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If you had both cameras and the same 50mm lens and looked through them both, the FF would be wider as it would be 50mm. The cropped body would be 50mm + the crop factor.

This is the same for EF and EF-S lenses. So a 50mm EF lens and a 50mm EF-S lens on a cropped camera would take the same shot.
 
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Thanks for the swift reply!!!.. So in essence a 50mm EF and 50m EF-S will give the same 'size' picture on a crop sensor camera.. Well that makes choosing lenses a bit easier! I just need to make the adjustment (in my head!) for use depending on what I really want on the crop sensor..

Really helpful to know.. I have been pondering this for a while without knowing which lens EF or EF-S!!!!
 
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chelleon said:
. So in essence a 50mm EF and 50m EF-S will give the same 'size' picture on a crop sensor camera..
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Yes, it will be zoomed in to the same size. The difference in 'zoom' comes from the body, not the lens, so 50mm is 50mm regardless of lens type.

As for 'what you want on a cropped sensor' just set your existing lens to 50mm or 35mm and force yourself to take shots at those lengths to see how they work fixed. What lenses are you looking at?
 
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I have a 50mm 1:1.4 at the moment (This I like!) and the usual kit lens, 18-55 EFS the 17-85 EFS Macro.

I am looking at the 24-105 L f/4 if I can ever find one that I can afford.. I'm not into the 2k bracket yet!

Have looked at the EF-S 17-55 f2.8 but for about the same money I 'believe' I should be able to get the 24-105...

Does sound remotely like a sensible plan?
 
chelleon said:
Have looked at the EF-S 17-55 f2.8 but for about the same money I 'believe' I should be able to get the 24-105...

Does sound remotely like a sensible plan?
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Depends on your needs, ones 2.8 and the other f4. You have the same focal length covered many times if you bought the 17-55. Try shooting everything at 24mm and see if it's wide enough for you I guess.
 
Thanks again.. I don't yet have the 2.8 (it's a toss up between) but I suppose I could work with the 17-85 for a few weeks to see if 24 would be sufficiently wide for my needs... Now that I know that 24 on the EF-S is the same 24 on the 24-105 etc, I can get an accurate picture.. (Pardon the pun!)
 
minnnt said:
What else did you want me to say??? The stated focal length of the lens is the same whether it is a full frame lens or a crop sensor lens... Which is what the OP wanted to know... wasn't it? It was certainly more helpful than you have been in this thread.
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Surely what the OP was asking was, is a 50mm EF on a Full Frame the same as a 50mm EF-S on a Crop Body. i.e will they give the same result.

Surely the answer is yes not stating something about 35mm being, and i quote "The stated focal length is in 35mm full frame terms" ???
 
The OP already knows that you have to take into consideration the crop factor which is clearly stated in the opening post. The question was is the focal length stated on an ef lens the same as it is on an ef-s lens... Now correct me if I'm wrong, but it is, isn't it? The focal length of the lens is in 35mm terms so a 50mm lens is indeed 50mm on a full frame camera. On a 1.6 cropped canon sensor it is still 50mm but will give the effective field of view of an 80mm lens due to the smaller sensor.
 
Guys, at this early stage of my you photographic career, Any and All knowledge is appreciated. :)

Perhaps I didn't word the question as succinctly as it should have been...

Thanks again to you both as it has certainly helped my understanding.
 
minnnt said:
The stated focal length is in 35mm full frame terms.
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No (well, yes a I see what you're trying to say, but no ;)).

The stated focal length is the focal length of the lens. Full stop. Period. It has nothing to do with full frame terms - a 35mm lens has a 35mm focal length - whether it is designed to fit on a compact camera or the largest sensored camera in the world.

What is different between EF and EF-S lenses is their ability to light different sized circles at the focal plane. An EF lens can light a circle that is larger than an EF-S lens, therefore can be used with a larger sensor.

Where equivalence comes in is field of view. A 50mm equivalent lens means it will give the same field of view as a 50mm lens on a full frame camera. The fact that a full frame camera is used as the reference point is due to convention rather than it being the ultimate reference point.
 
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minnnt said:
I never mentioned a 35mm focal length...
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I did. I was taking issue of the words full frame terms not the specific focal length.
 
minnnt said:
Haha, so what did i say that was wrong then?

Focal lengths that are written on the lens are in full frame terms...
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They're not "in terms" of any frame size be it 35mm, medium format or APS-C.

Bob
 
I lively discussion.. !!! I hope I haven't started something!! :-(
 
Good man! I now have a question about how to edit photos out of OS X photo folders without having to export the darn things first. Wish me luck!!!
 
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