EF Lenses on T3I

[Kolourl3lind]

I just want to know if my math is correct on this point. These are the equavalent focal point of some EF prime lenses on the T3i. I multiply by 1.6x crop right?

24mm EF would be 38mm
30mm EF would be  48mm
85mm EF would be 136mm

Is that correct or am I off?

[RobertTheFat]

That's about right, but it's easier in the long run to simply start thinking in terms of what lenses do what on an APS-C camera. I.e., a "normal" lens is about 31mm; 50mm is a mild telephoto or portrait lens; a normal zoom is about 18-50mm; etc. Trying to keep track of the conversion factors is just a source of unnecessary confusion.

[Kolourl3lind]

wow it's easier just to get a EOS camera

[amfoto1]

Understand that there is no change to the actual focal length....

50mm is still 50mm. Doesn't matter if it's an EF lens or an EF-S lens or any other lens type.

All that changes is how that 50mm behaves when you put it on different film or sensor formats.

- 50mm on a point-n-shoot camera with a tiny digital sensor it acts as a powerful telephoto.

- The same 50mm on an APS-C size sensor such as T3i is a short telephoto.

- Put it on a so-called full frame camera and it's a standard lens.

- Or put it on a medium format digital or film camera and it will act as a wide angle.

But it's still 50mm, regardless.

One of the few reasons to "do the math" is if you used to use 35mm film or full frame digital camera and now want to get lenses for use on a T3i that will deliver about the same that you saw on that previous camera. In other words, the only reason to do these calculations is if you have preconceived notions about how lenses will perform.

Another reason might be if you use both full frame and crop cameras, switch back and forth between them and/or share lenses between them.

But if you've never used a camera before or have only ever used APS-C crop cameras and are simply looking for lenses to use on the T3i, it serves little purpose to "do the math".

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Kolourl3lind wrote:

wow it's easier just to get a EOS camera

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Huh? Not sure what you mean....

T3i is an EOS camera. So are D1X, 5DS, 5D Mark III, 7D Mark II, 70D, T6s, T5i, SL1, T5...

In fact, every 35mm film SLR and digital DSLR Canon has made for the past 25 years or so has been an EOS camera.

Lenses for T3i couldn't get much easier than they are, if that's what you mean... Any EF (full frame) or EF-S (crop only) lens can be used on it. Any modern third party (Sigma, Tokina, Tamron) lens made for Canon camaras can be used on it.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER 

[Kolourl3lind]

I stand corrected. BY EOS I meant ES full frame camera and not the EOS EF-S Rebel cameras.

Also, I do switch between my T3I and 6D very often when I photograph an event. This make photographing difficult when I don't have the same viewpoint using the same lens wiith each camera.  What I trying to do is buy a decent wide angle prime to fit on the T3i. This will allow me use the T3i just for wide angle shooting at one focal length and get decent photo quaility compared with 6D using a zoom lens.

This is the best setup I can think of otherwise it's just easier to us my 6D and switch lenses instead of carrying two camera.

[ebiggs1]

IMHO, this is backwards, to me.

"This will allow me use the T3i just for wide angle shooting at one focal length and get decent photo quaility compared with 6D using a zoom lens."

I would prefer to use a good WA to normal zoom on the 6D and a good normal to tele zoom on the T3i.

My typical (basic) wedding set up had a 7D (cropper) on a tripod at the back of the church or venue with a 100-400mm on it.  While I had my 24-70mm f2.8 on a 1Ds Mk III (full frame).

I also like my 70-200mm f2.8 on my 1D Mk IV, which is a tweener cropper at 1.3x.

[amfoto1 · Accepted solution]

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@Kolourl3lind wrote:

I stand corrected. BY EOS I meant ES full frame camera and not the EOS EF-S Rebel cameras.

Also, I do switch between my T3I and 6D very often when I photograph an event. This make photographing difficult when I don't have the same viewpoint using the same lens wiith each camera.  What I trying to do is buy a decent wide angle prime to fit on the T3i. This will allow me use the T3i just for wide angle shooting at one focal length and get decent photo quaility compared with 6D using a zoom lens.

This is the best setup I can think of otherwise it's just easier to us my 6D and switch lenses instead of carrying two camera.

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Okay, now it's clearer what you're trying to do, and that you're switching back and forth between two formats.

However, there are very few primes that are ultra wide on a full frame camera and still very wide on an APS-C crop sensor. 24mm is a nice wide angle on a full frame camera, but only behaves as a slighlty wide "normal" when used on a crop sensor camera. I have and use a Canon EF 20mm... quite wide on full frame. It's nice, but only a moderately wide lens (32mm FF equivalent) on a cropper.

There are Canon 14mm (original and Mark II). And there is a manual focus only Zeiss 15mm ZE. Also there are a few 17mm lenses. These are rather pricey, though. And, on a crop sensor camera a 17mm is only modestly wide.

In the past both Tamron and Sigma made 14mm full frame compatible lenses. Those were of questionable image quality and discontinued many years ago... so will only be available used, if you can find them.

There also is a Samyang/Rokinon 14mm lens that's full frame compatible and affordable, but manual focus and manual aperture only, so would be slower to work with. It sells for a bit more than $300 and also can be found in Bower, Dot Line, ProOptic, Vivitar and other brand names (Vivitar calls it a 13mm, altho it's the same lens.) This lens has strong "moustache" distortion, but there are softwares that can correct it.

Another possible consideration, all the 14, 15mm and many of the 17mm... and some of the widest of the full frame-capable ultrawide zooms, too... tend to have very strongly convex front lens elements that won't allow standard screw-in filters to be fitted.

There simply aren't many truly wide prime lenses for crop sensor cameras. And most primes and zooms that are wide on FF, are only slighlty or moderately wide on crop.

If you want to use the wide lens on the crop sensor T3i only, there are some good zooms you really should consider.

Canon recently introduced an EF-S 10-18mm IS STM that's a real bargain at $300 list price and even less on sale currently. I haven't used it yet, but have heard lots of good reports. No, it's not as sharp from edge-to-edge as some others, but it's pretty amazingly good at the price (which is at least $100 less than any other ultrawide zoom... $200 or more less than most).

Canon's EF-S 10-22mm USM has been around for some years, sells for about $650, and in my opinion is one of the best ultrawides for crop sensor cameras from any manufacturer. It's very well corrected, sharp from edge to edge with well controlled chromatic aberration, reasonably good build quality, able to use standard 77mm filters and has exceptionally good flare control.

Sigma offers two versions of 10-20mm and the widest of all in an 8-16mm. Tamron offers a 10-24mm. Tokina has offered the fastest in an 11-16/2.8, as well as a 12-24/4 (both of which are now discontinued but still can be found). Tokina is currently introducing new 11-20/2.8 and 12-28/4 models.

However, all the above zooms are "crop only" (at least technically, see below).

If you want to use the lens on both your T3i and 6D...

Canon's new 11-24/2.8L would work great... but is very pricey (nearly $3000).

Sigma offers a 12-24mm that's full frame and crop sensor compatible. It's rather pricey and has a significant amoung of distortion.

There are various 16-28mm, 16-35mm, 17-35mm, 17-40mm that are full frame compatible... tho all these are just moderately wide on the crop T3i.

An interesting possiblitity... I can tell you for certain that a Tokina 12-24/4 is a good lens on crop cameras, and that it's partially usable on full frame. I've tested it as wide as 17 or 18mm on my 5DII, before it starts to show some vignetting. I understand the Tokina 11-16/2.8  can be used on FF, too... though only at it's 16mm setting.(I haven't used, so can't say about the two new Tokina models.)

FYI:

Common parlance for Canon EOS digital cameras is "APS-C/1.6X crop" and "full frame/1.0X".

Or just "crop sensor", "crop" or "cropper" vs "full frame" or "FF".

Canon lenses are either "EF/full frame compatible" or "EF-S/APS-C crop only".  Only Canon makes EF-S lenses that use a variation on the EF mount, designed to not allow the lenses to physically attach to "incompatible" cameras.

There are no "ES" or even "EF" cameras and few people refer to "EF-S cameras". That's because the APS-C or crop cameras can use both EF and EF-S lenses... while full frame cameras can only use EF lenses. EF-S lenses will not even physically mount onto the full frame camera models such as your 6D (nor onto the third format Canon used to offer: APS-H or 1.3X... which also require EF lenses).

Among third party lens manufacturers there are no EF-S lenses at all. Sigma, Tokina and Tamron all only use EF mount, regardless. Although they may be possible to mount on a full frame camera, many of the lenses they offer still are "crop only"... They do not produce a large enough image circle to cover the entire area of a full frame sensor, so will heavily vignette. Still, some may work partially (as noted above).

Canon EF, Tamron "Di", Tokina "FX" and Sigma "DG" lenses are all full frame and crop sensor compatible.

Canon EF-S, Tamron "Di II", Tokina "DX" and Sigma "DC" lenses are all crop-only.

Hope this helps!

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & EXPOSUREMANAGER