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04-18-2009, 09:30 AM   #16
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QuoteOriginally posted by asw66 Quote
I'll be travelling to HK in a couple of months, and I think a decent prime would be good for street/night shots. I can get either the FA 50 or the DA 40 for roughly the same price ... which would you recommend?
I'd be carrying a fast normal (such as the FA35/2.0) for urban scenery. A wide prime (DA21) is also very nice but not as important if you have a zoom that perfoms well at that focal length.

Also, no UV filters for night shots.

04-18-2009, 12:18 PM   #17
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QuoteOriginally posted by Cosmo Quote
It would be easier if you used film, but the crop factor really screws this up. Lenses of focal length 28-35 are good for film/FF, but when the angle of view is decreased due to the crop factor to that similar of a 40mm lens, the perspective is horrible.
One man's horrible is another's perfect. I happen to love the FOV of 28mm on APS-C, almost as much as I love 40mm. 21mm doesn't do much for me at all.
04-18-2009, 12:22 PM   #18
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One other consideration that usually gets mentioned but hasn't been thi time around:

All else equal, I'd get the 40 if or no other reason than the fact that if you decide later you want something a little faster and/or longer, you can always get a cheap manual focus 50 on a moment's notice for practically nothing. I imagine Hong Kong has pawn shops; you could even do it after you arrive. Whereas if you get the 50 and decide later you don't like the wide open performance and/or find it too long, it's still going to cost over $200 to add the DA40.
04-19-2009, 01:42 AM   #19
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QuoteOriginally posted by Marc Sabatella Quote
One man's horrible is another's perfect. I happen to love the FOV of 28mm on APS-C, almost as much as I love 40mm. 21mm doesn't do much for me at all.
agreed on that.
I really like 40 on APSC and I used to have Tokina 28/2.8 MF. I loved it's FOV on APSC, but it wasn't good lens so I wanted to get F or FA28/2.8. Couldn't get one so I settled for 31ltd. And it's FOV on APSC is great. Love it...
BR

04-19-2009, 02:52 AM   #20
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QuoteOriginally posted by Marc Sabatella Quote
One man's horrible is another's perfect. I happen to love the FOV of 28mm on APS-C, almost as much as I love 40mm. 21mm doesn't do much for me at all.
It's not the FOV, more the focal length.
04-19-2009, 03:55 AM   #21
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i like fast primes... the 40 isnt fast enough imo
04-19-2009, 07:30 AM   #22
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It's fast enough for 90-95% of situation wise man uses it in...
Same way, you could say 50/1.4 is not wide enough...

BR
04-19-2009, 07:46 AM   #23
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QuoteOriginally posted by Cosmo Quote
It's not the FOV, more the focal length.
What difference other than FOV is there? OK, it has an effect on DOF too. But you mention the word perspective, and you should be aware that focal length has nothing to do with focal length. It is a function of subject distance and subject distance only.

04-19-2009, 07:52 AM   #24
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QuoteOriginally posted by WerTicus Quote
i like fast primes... the 40 isnt fast enough imo
That's why I recommend the 40 plus a cheap 50 - you get the advantages of the 40 (wider FOV, incredibly fast AF, small size, considerably sharper across the frame, and fast enough for "most" situations), but a 50 also for situations where you need the narrower DOF or faster shutter speeds in low light.
04-19-2009, 08:05 AM   #25
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QuoteOriginally posted by Marc Sabatella Quote
What difference other than FOV is there? OK, it has an effect on DOF too. But you mention the word perspective, and you should be aware that focal length has nothing to do with focal length. It is a function of subject distance and subject distance only.
Longer focal lengths compress perspective. While a 35mm lens on a aps-c sensor, 50mm on film/FF and 80mm on medium format all have a simliar angle of view, they all have a very different perspective.

I hate using 28mm on APS-C, but I love 50mm on film and 80mm on my yashica.
04-19-2009, 09:18 AM   #26
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QuoteOriginally posted by Cosmo Quote
Longer focal lengths compress perspective. While a 35mm lens on a aps-c sensor, 50mm on film/FF and 80mm on medium format all have a simliar angle of view, they all have a very different perspective.
That's the specific myth I was referring to. It simply isn't true. The only reason that longer focal lengths are said to compress focal length is that they encourage you to take the shot from a greater distance. Pictures taken with the lens/camera combos you mention are completely indistinguishable in terms of perspective.

There are any number of illustrated articles online that should finally put this myth to rest. One of them is:

Common photography myths

See in particular the three street scene shots. The second and third were shot from the same position with a 20mm and 100mm lens respectively, but the 20mm shot was cropped (as happens with APS-C versus 35mm) to provide the same FOV. There is *no difference* in perspective in these two shots.

QuoteQuote:
I hate using 28mm on APS-C, but I love 50mm on film and 80mm on my yashica.
Well, 28mm on APS-C is noticeably wider than 50mm on 35mm film. And it's entirely possible that the specific 28mm lens you are using might introduce pincushion distortions. And of course, the viewfinder is smaller on most APS-C cameras than most 35mm cameras, which further affects our perception of the shot we are about to take.

But once you take the shot, perspective is identical from a given vantage point regardless of lens or camera. If it weren't, the last five centuries of representational art would not have happened - the principles of perspective have been well-known for that long. In fact, we're just about coming on the 500th anniversary of the first recorded examples of the elucidation of these principles (early 1400's).
04-19-2009, 03:45 PM   #27
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Now I knew all about that, yet I still typed all that crap. I feel so stupid.

I think it's cause I assumed when you use the same lens on different formats, perspective appears to change. While this is not true when you stand in the same place relative to the subject, when you move so that the subject fills the frame to the same extent in each case, perspective changes.

I have realised that a 35mm lens on aps-c has the same perspective as 50mm on film. But I still hate using my 28mm on aps-c, maybe it's a combination of deeper DOF and the small view finder, but I just don't like what I see when I look through the viewfinder.
04-19-2009, 08:37 PM   #28
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QuoteOriginally posted by Marc Sabatella Quote
That's the specific myth I was referring to. It simply isn't true. The only reason that longer focal lengths are said to compress focal length is that they encourage you to take the shot from a greater distance. Pictures taken with the lens/camera combos you mention are completely indistinguishable in terms of perspective.

There are any number of illustrated articles online that should finally put this myth to rest. One of them is:

Common photography myths

See in particular the three street scene shots. The second and third were shot from the same position with a 20mm and 100mm lens respectively, but the 20mm shot was cropped (as happens with APS-C versus 35mm) to provide the same FOV. There is *no difference* in perspective in these two shots.



Well, 28mm on APS-C is noticeably wider than 50mm on 35mm film. And it's entirely possible that the specific 28mm lens you are using might introduce pincushion distortions. And of course, the viewfinder is smaller on most APS-C cameras than most 35mm cameras, which further affects our perception of the shot we are about to take.

But once you take the shot, perspective is identical from a given vantage point regardless of lens or camera. If it weren't, the last five centuries of representational art would not have happened - the principles of perspective have been well-known for that long. In fact, we're just about coming on the 500th anniversary of the first recorded examples of the elucidation of these principles (early 1400's).
Practically speaking it does matter. If you want a flatter perspective you can either take ten steps back and then crop the result or take ten steps back and use a longer lens. Typically you'll want to use the latter, right?

So a good rule of thumb is that when you take two photos with similar composition, the longer lens will give you a flatter image and the shorter lens will give you a deeper image.
04-19-2009, 11:39 PM   #29
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QuoteOriginally posted by ILoveVerdi Quote
Practically speaking it does matter. If you want a flatter perspective you can either take ten steps back and then crop the result or take ten steps back and use a longer lens. Typically you'll want to use the latter, right?

So a good rule of thumb is that when you take two photos with similar composition, the longer lens will give you a flatter image and the shorter lens will give you a deeper image.
Oh, yes, certainly, when talking about using two lenses of different focal lengths on one camera, there is this very real practical side to it - the difference in FOV *will* tend to cause you to shoot from different positions.

But we were talking about comparing lenses on different cameras that actually provide the same FOV (eg, 28mm on APS-C, 42mm on FF). In this case, FOV is the same, so there is no incentive to change position, and thus no difference in perspective.

I do suspect the smaller viewfinder causes us to perceive the scene a bit differently in the case of 28mm on APS-C versus 42mm on FF, though. The picture might come out the same, but we might not feel the same when taking it. It took me quite a while to warm to 28mm on APS-C - not that I have recent enough experience with a 35mm SLR to shape my expectations. But I just tend to like the view in the viewfinder better with my DA40, presumably because it is closer to life size and comes closer to providing the same FOV as I'd expect if the viewfinder had no optics but were just a hole cut in the camera.

Last edited by Marc Sabatella; 06-20-2009 at 09:21 AM.
06-20-2009, 05:54 AM   #30
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Thanks for your input, folks

In the end, my buying decisions were driven by happenstance, i.e. which deals came through eBay at the right time. I bought a DA40 and Sigma 10-20 (both 2nd hand), and I'm very happy with both.

The DA40 in particular has replaced my kit lens as my default. I even like the screw-on lens cap.
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