More lens confusion

Lucian said:
How to determine if a lens is rated for FF or cropped frame? With Canon EF=FF right?
What about Tamrons and Sigmas? How to tell? For example, I'm interested in this lens, http://www.bhphotovideo.com/c/produ...01C_700_70_200mm_f_2_8_Di_LD.html#accessories.
But is the 70-200mm based on a FF camera? So would this lens be closer to a 300mm?
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Yep, EF is Full Frame, EF-S is APS-C.

Retailers should let you know in one of three ways.

1) it will be in the item title. For example: Tamron 17-55mm f/1.4 Full-Frame (wouldn't that be a nice lens...)

2) they will make a special note about it. I believe either BHP or Adorama has a little box below the item that says "NOTE: THIS LENS IS ONLY FOR CROP SENSORS" or something to that effect.

3) It will be in the item description. After clicking on the "features" tab on the page you linked to, I read
When mounted on an APS-C sensor size digital SLR camera, it provides a focal length equivalent of 112-320mm.
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So that lens, in particular, is a FF lens. Just have to hunt around a bit!
 
The only concern that you should have about whether a lens is intended for APS-C or not is regarding your plans for the future. In other words, do you imagine yourself switching to full frame later? If the answer is yes, then you should try to avoid lenses designed for APS-C. Otherwise, it really doesn't matter. A 70-200mm lens will give you the same field of view on the 7D no matter if it's designed for full frame or for APS-C.
 
ydgmdlu said:
A 70-200mm lens will give you the same field of view on the 7D no matter if it's designed for full frame or for APS-C.
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sigh, I thought i had this down. If a 70-200mm designed for full frame cameras is mounted on a 7d, aren't you gonna get 112-300 equivalent frame? Isn't that how the 1.6x thing woks?
 
Okay so the Tamron 17-50 that everyone loves is in fact a FF because on Amazon we have this sentence:

"Tamron's new SP AF 17-50mm F/ 2.8 acts RDI II VC covers the heavily used 17-50 MM focal distance range (angle of view equivalent of 26-78 MM when converted to the full frame format) making it an extremely versatile, high performance zoom lens. "

Am I right? Am I right? Please tell me I'm right because I ordered the lens yesterday. :)

Although I think there is a typo as it says when converted to 'full frame' as opposed to 'cropped for APS-C' or whatnot.
 
Lucian said:
sigh, I thought i had this down. If a 70-200mm designed for full frame cameras is mounted on a 7d, aren't you gonna get 112-300 equivalent frame? Isn't that how the 1.6x thing woks?
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Just forget about the whole crop factor thing. Crop factor only matters if you come from a still photography background, and you're used to shooting full frame.

If you mount a 70-200mm lens designed for full-frame onto the 7D, you'll have a field of view equivalent to a 112-320mm lens on a full-frame camera (such as the 5D).

If you mount a 70-200mm lens designed for APS-C onto the 7D, you'll STILL have a field of view equivalent to a 112-320mm lens on a full-frame camera (such as the 5D).

There are only two differences between the above two lenses:
1) The projected image circle for the APS-C lens is smaller than the full-frame lens.
2) The APS-C lens is probably smaller, physically, than the full-frame lens.

Once again, the field of view (or angle of view, if you prefer) is exactly the same. The choice between APS-C lenses and full-frame lenses depends on what you feel that your future needs might be. If you buy a full-frame camera later, you won't be able to use your APS-C lenses because they'll be heavily vignetted. But they'll still offer the same FOV.
 
EDIT: Got in a bit late on this one!

Lucian said:
sigh, I thought i had this down. If a 70-200mm designed for full frame cameras is mounted on a 7d, aren't you gonna get 112-300 equivalent frame? Isn't that how the 1.6x thing woks?
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Lucian, this is in no way meant to be an offense to you or anyone else on here, but whoever came up with the whole "crop" comparison mess should be shot in the eye.

What he is saying is that a Full Frame 70-200 and a APS-C 70-200 will look the same on the camera. The APS-C just has a smaller image circle so less of its image is "wasted" by not projecting onto the sensor. The Full Frame is, in a way, overkill - it is projecting an image much larger than the sensor.

You are correct: ANY 70-200 lens you can make fit on the 7D will have a field of view roughly equivalent to that of a 112-300 on a Full Frame camera.
 
Chance White said:
Okay so the Tamron 17-50 that everyone loves is in fact a FF because on Amazon we have this sentence:

"Tamron's new SP AF 17-50mm F/ 2.8 acts RDI II VC covers the heavily used 17-50 MM focal distance range (angle of view equivalent of 26-78 MM when converted to the full frame format) making it an extremely versatile, high performance zoom lens. "

Am I right? Am I right? Please tell me I'm right because I ordered the lens yesterday. :)

Although I think there is a typo as it says when converted to 'full frame' as opposed to 'cropped for APS-C' or whatnot.
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Wrong. It's not full-frame because the literature that you've quoted specifically indicates so. I've highlighted the relevant portion for you. There would be no need for such a sentence if the lens were intended for full frame in the first place.

As far as I know, there is no such thing as a 17-50mm (or 16-50mm, or 18-50mm) lens for full-frame cameras. Such a lens would be HUGE and prohibitively expensive.
 
Lucian said:
sigh, I thought i had this down. If a 70-200mm designed for full frame cameras is mounted on a 7d, aren't you gonna get 112-300 equivalent frame? Isn't that how the 1.6x thing woks?
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Don't worry you DO have it down. Basically if a lens has been made for a APS-C 1.6xcropped sensor (i.e. not full frame EF, and therefore EF-S) the only difference is that it should be cheaper due to the manufacturers not using as much glass. So... the FOV is going to be 1.6x whatever any lens says its Focal length is, no matter what abbreviations are within its name.

Hope that helps.
 
ydgmdlu said:
Wrong. It's not full-frame because the literature that you've quoted specifically indicates so. I've highlighted the relevant portion for you.

As far as I know, there is no such thing as a 17-50mm (or 16-50mm, or 18-50mm) lens for full-frame cameras. Such a lens would be HUGE and prohibitively expensive.
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Quoted for truth.

Check out BHP here: http://www.bhphotovideo.com/c/product/423714-REG/Tamron_AF016C700_17_50mm_f_2_8_XR_Di.html

They note:
Not compatible with 35mm or digital cameras with image sensor larger than APS-C size
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In other words, its an EF-S lens made for APS-C sensors.
 
Hey Michael, we should author an FAQ here on lenses and crop factors, etc. Whenever someone asks about such things, we always seem to be the ones providing the clarifications.
 
Okay... so I thought I understood this, now I don't...

Is it all about relativism? What I mean is, most films are shot S35 which is inclusive of the 1.6 crop, which means most of us are used to seeing 28mm look like it does in a film, which has a 1.6 crop. So if you are doing cinematic work, a 28mm lens will look EXACTLY like it should look, how you've seen it in motion pictures, and you don't need to worry about crop factors... is this correct?

The only way you notice it is if you are familiar with photography where FULL FRAME lenses are more prevalent...

The more this is explained it seems the more people become confused. I definitely think there should be a FAQ or sticky.
 
Chance White said:
Is it all about relativism? What I mean is, most films are shot S35 which is inclusive of the 1.6 crop, which means most of us are used to seeing 28mm look like it does in a film, which has a 1.6 crop. So if you are doing cinematic work, a 28mm lens will look EXACTLY like it should look, how you've seen it in motion pictures, and you don't need to worry about crop factors... is this correct?

The only way you notice it is if you are familiar with photography where FULL FRAME lenses are more prevalent...
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Absolutely, 100%. You got it, pal. Now don't think any bit more about crop factors, and you'll be fine.

Though, technically speaking, S35 (a) not the most common motion picture format and (b) less of a crop compared to FF (probably more like 1.45x). REGULAR 35mm (not Super 35) is about the same size as Canon APS-C.
 
Very informative. Thank you for helping me get past this challenging hurdle of comprehension known as 'crop factors'. Next up, crop circles, which most believe the most challenging of all crop style mental hurdles.
 
ydgmdlu said:
Absolutely, 100%. You got it, pal. Now don't think any bit more about crop factors, and you'll be fine.

Though, technically speaking, S35 (a) not the most common motion picture format and (b) less of a crop compared to FF (probably more like 1.45x). REGULAR 35mm (not Super 35) is about the same size as Canon APS-C.
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I thought I understood it until Chance posted this. Thanks Chance. I'm going to go hang myself now. I leave my 7d to the first DVXUSER to say "Mine".
 
Lucian said:
I thought I understood it until Chance posted this. Thanks Chance. I'm going to go hang myself now. I leave my 7d to the first DVXUSER to say "Mine".
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In that case, would you mind stating exactly what you don't understand, or where you are confused, so that we may address those points directly?
 
You only have to worry about crop factors if you're working with two different image formats. Are you also doing full-frame still photography?

Otherwise, simply forget about crop factors and learn what angles of view you get with each focal length on a given image format (in this case, APS-C).
 
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