[Pentaxor]

I can't wait for the comparison! I now have the FA* 85, A* 85 and FA77 at home, but no Sigma to compare it with

By the way, as I have shown before (and it's quite logical): 55mm f/1.4 on APS-C is almost the same as 83mm f/1.9 on FF with regards to relative subject's size and DOF, while the camera is at the exact same spot.

Proof (and actually I should have stopped down the Takumar a little bit to f/2.1 to make the bokeh comparable):

DA* 55/1.4 on APS-C:


83mm f/1.9 Takumar on FF:

this is true and I believe this was tackled on DOF equivalence topic. the things to consider however is that speed (exposure) is still not the same (an f1.4 is still has faster aperture speed than an f2) and also involves cropping which eliminates the purpose the need for certain focal lengths but this is only as good depending on the resolving power of the lens at certain distance and camera. obviously, I don't think that someone would shoot a headshot photo exclusively with a 35mm lens at 30 ft (you lose significant resolution at cropping). hence, the need for other focal lengths becomes necessary. if the 55mm were enough with regards to resolution, I think that everyone in photography world be extremely happy. that's why someone still needs something of a short telephoto like an FA77. so why not an 85mm as well? one would say because of FOV, and then we go back full circles again about validity of use of certain focal lengths again. point is, this is more about people who prefer shooting with an 85mm lens because they are comfortable to it's perks, be it FOV, DOF, IQ and resolution, character rendering (subjective) and spacing (shooting). I think this is the reason inspite of having an FA77, you have other 85mm as well which I don't think that also restricts you from using them on an APS-C camera by virtue of equivalence.

[jstevewhite]

Not quite correct.
FL of the lens has indirect effect on perspective.
What actually does matter is distance between sensor/film plane and subject.
Easy exercise to is, slap zoom on your camera and take a series of shots of the same subject from the same spot. Then take the widest shot and crop it to match the framing on the longest shot and then compare. The perspective will be the same.
What does change perspective is when you change the distance between camera and object. With the same zoom, take a picture on long(ish) end and then zoom out and recompose to match framing. Then compare your shots.....


If you keep the same lens, this is correct but if you change lens with the same ratio as sensor size then it's incorrect.

I think what's confusing the issue is the magnification of the focusing screen. Because the APS/C systems use the same flange-to-'film'-plane as FF (so we can use old lenses) we have similar distances between our eyes and the focus screen. An APS/C actually *looks* smaller. So when you put a 50mm on either one (as they have the same viewfinder magnification) it "looks" the same (perspective wise) in the viewfinder, and a 35mm "looks" like a wide-angle (perspective wise). By "looks like" I'm referring to the visual experiment I mentioned some time ago in this thread - put a 50mm on a FF and an APS/C, then look through the camera with one eye, and open the other. You'll see that in both systems the perspective looks the same as the open, un-camera'd eye. And if you put a 35mm on the APS/C and look through the camera with one eye, you'll see that the camera shows (apparently) wide-angle perspective.

I'm well aware that the final capture has the same perspective (the 35mm w APS/C, the 50mm w FF) and FOV, but compositionally, when you look through the viewfinder, they 'feel' different. If we used a shorter flange-to-sensor difference so we could magnify the focusing screen to the same apparent "size" as the FF (by moving it optically closer to the eye), then we would see the same "visual perspective" as we do with 50mm on FF.

[axl]

I think what's confusing the issue is the magnification of the focusing screen. Because the APS/C systems use the same flange-to-'film'-plane as FF (so we can use old lenses) we have similar distances between our eyes and the focus screen. An APS/C actually *looks* smaller. So when you put a 50mm on either one (as they have the same viewfinder magnification) it "looks" the same (perspective wise) in the viewfinder, and a 35mm "looks" like a wide-angle (perspective wise). By "looks like" I'm referring to the visual experiment I mentioned some time ago in this thread - put a 50mm on a FF and an APS/C, then look through the camera with one eye, and open the other. You'll see that in both systems the perspective looks the same as the open, un-camera'd eye. And if you put a 35mm on the APS/C and look through the camera with one eye, you'll see that the camera shows (apparently) wide-angle perspective.

I'm well aware that the final capture has the same perspective (the 35mm w APS/C, the 50mm w FF) and FOV, but compositionally, when you look through the viewfinder, they 'feel' different. If we used a shorter flange-to-sensor difference so we could magnify the focusing screen to the same apparent "size" as the FF (by moving it optically closer to the eye), then we would see the same "visual perspective" as we do with 50mm on FF.

I do understand what you are saying but for the actual outcome it's largely irrelevant.
The "feel" of the 50 or 85 for that matter might be the same on APSC, FF or 645 for that matter. But if you want to frame the same way om all 3 systems you'll have to make considerable adjustments to distance between you and subject and that will change the perspective achieved in the picture...

[jstevewhite]

I do understand what you are saying but for the actual outcome it's largely irrelevant.
The "feel" of the 50 or 85 for that matter might be the same on APSC, FF or 645 for that matter. But if you want to frame the same way om all 3 systems you'll have to make considerable adjustments to distance between you and subject and that will change the perspective achieved in the picture...

On a MF camera, the "normal" lens *looks* normal because the flange-to-film distance is different, and the screen magnification is different; on my Hassy, with eye-level finder, the two-eyes-open thing worked pretty well, whereas a 50mm "looked" like a wide angle.

I think it can affect your perception as you compose things, although you're absolutely right, in a technical sense there's no difference in outcome. It just affects the way you *see* things.

[LFLee]

I don't know.... all things aside, I like the built of FA* 85 more than the Sigma. But I am sure people with the Sigma 85 f.14 can take better pic than me w/ a FA* 85 though.....

[Pentaxor]

I do understand what you are saying but for the actual outcome it's largely irrelevant.
The "feel" of the 50 or 85 for that matter might be the same on APSC, FF or 645 for that matter. But if you want to frame the same way om all 3 systems you'll have to make considerable adjustments to distance between you and subject and that will change the perspective achieved in the picture...

that is a compromise when you want to frame each lens the same. distance is one factor, the others are resolution and DOF. if we speak about one particular lens, for example a particular 85mm being used on APS-C, FF, and MF, the 85 is still an 85mm, except with the compromises of being limited to sensor size (FOV cut-off), DOF, and camera pixel resolution for large crops. as far as lens equivalence per system used, I think the obvious answer is that it's just not equal if we were to consider exposure, magnification and IQ, and we dismiss FOV and DOF equivalence. so basically, we dont expect a 50mm lens to produce a miracle and do a 200mm lens job with respect to resolution.

for what it's worth, shooting distance would play a huge role in the difference of a lens' focal length perspective and resolution.

[icypepsi]

This is only true, again, if you don't change the camera subject distance!
Regards

Thanks. But wrong about me. I already mentioned the change required in subject distance to get the same framing, in a previous post also. I thought it was obvious from Pentaxor's example, like you noticed, and esp. because we are talking about the same FoV.

[farfisa]

Looks like we scared off the guy posting the pics--sorry dude!

[jstevewhite]

Looks like we scared off the guy posting the pics--sorry dude!

Maybe he's just having more fun shooting pictures rather than talking about it!

[outsider]

Maybe he's just having more fun shooting pictures rather than talking about it!

Haha, if you're talking about me, I find the "heated" debate here enlightening, fascinatging and at times, entertaining. It's good to know were so passionate about our science. I posted some more samples in another thread, thinking you may have seen them already. If not, here are some, all shot between f1.6 and 2.0:

[farfisa]

Very nice!

Starting to see a bit more of what this lens does with colour--colour and contrast look great at wide apertures.

I'd like to see a bit more background, maybe not so close the the subjects, but hey, looks like you've got a style going on

Thanks for sharing!

[Pentaxor]

thanks for sharing. I'm pretty much sold on the sharpness, contrast and most especially the bokeh. the colors look very good although I would love to see more of that and other subjects aside from portraits. could be abstract, a bit of macro, landscape, street and candid would be nice.

[LFLee]

outsider.... nice. Where did you find so many beautiful people to shoot?
I like this the most:
4 16 11 105 by Atiim D. Jones Photography, on Flickr

Lee

[outsider]

outsider.... nice. Where did you find so many beautiful people to shoot?
I like this the most:
4 16 11 105 by Atiim D. Jones Photography, on Flickr

Lee

Just walking around Omaha, Nebraska, downtown. You'd be surprised how many beautiful people there are we overlook, walking the streets everyday. However, much credit must go to the camera/lens. It's a k5 with sigma 85 1.4. They say there are no great photographers, just great photographs, but it should go something like there are great cameras, lenses that take great photographs. The girl that looks like a model was just a normal, young girl walking with her friend. I intended to take just 3 or 4 shots, but she seemed to rather enjoy it, so I kept shooting. The great sensor of the k5 really brings out the lifelike feel to any picture you take

[outsider]

outsider.... nice. Where did you find so many beautiful people to shoot?
I like this the most:
4 16 11 105 by Atiim D. Jones Photography, on Flickr

Lee

Every week, I walk the streets taking pictures of random people. I ask to take their portrait and the approval rate is surprisingly high, but I think it depends on how you approach them. It's a lot of fun because of the variety of faces and expressions and the lighting conditions. My favorite scenario is taking a picture beneath a tree in clear, sunlit sky. You get an interesting pattern on the face that evokes a different emotion each time. Overcast is always a winner too. You don't have to worry about purple fringing and I still have enough shutter speed to get sharp photos and color/emotion of the portrait is more somber/serene.