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03-29-2011, 04:56 PM   #46
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QuoteOriginally posted by Marc Sabatella Quote
Perhaps, but I'd assume they either have a rare defective copy, or else their test methods were flawed - like they failed to focus accurately, or tested sharpness in an out of focus area. Both are pretty common problems with wide angle lenses.

But I'd challenge you to test for yourself in the way I described. Take a head & shoulders shot of a person with the DA15 (you'll be shooting from quite close, of course), carefully focusing on one particular part of the face because DOF will be shallow enough that whole face can't be in focus at once. Then do the same with the other two lenses (from progressively farther away, of course). Then compare the in-focus areas at 100%. I believe your impression of the DA15 will change instantly.
I will definitely try that Marc. I went back over some of my pictures and did find one, a sculpture, at f/4 that was very sharp. It was about 10' above my head. The last shots I took that turned me away from f/4 was at close range. I could have been crowding the in-focus area or the DOF was shallow enough it was out of focus. As soon as I stopped down to f/8 all was in focus but the edges, which was no big deal. I already love working with the 15, if I find I can shoot with confidence at f/4 I'll love it that much more.


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Fair enough. Then my answer is that the DA15 absolutely without question is the sharpest lens when shot wide open that I have ever used (a couple of dozen lenses), and its numbers on photozone bear that out.

Second place among lenses I have experience with would be the DA70, followed by the DA40. Here, the numbers don't make those lenses stand out quite so much, so it's mostly a subjective notion.

The M50/1.7 isn't particularly sharp at f/1.7, but by f/2.8 it is as sharp as anything else out there. The M100/2.8 and M28/2.8 are both sharp enough wide open that you'd be a fool to stop down and thus give up shutter speed just to get them a little sharper still. I could (and have!) say essentially the same about *any* lens, but these stand out among the M series lenses I know (28, three different 50's, 100, 120, 135, and 200, plus the 85 by reputation).

The DA*60-250 is, like the DA15, only f/4, and in this focal length range that's an issue for low light shooting, but it's also impressively sharp for that aperture and focal length range. I don't own it, but did have the chance to try it out, and have seen others' images.

I don't own any of the FA Limiteds, but all data and images I've seen suggest they are all incredibly sharp by f/2.8, but noticeably less so at f/2 or beyond. Similarly for the FA35.

Most macro lenses are really sharp wide open.

Basically, most primes that are f/2.8 or so max are sharp enough to use wide open with no hesitation. Most primes that are f/2 or faster are quite a bit softer wide open, but of course, stopped down to f/2.8 become as good as or better than the f/2.8 primes.
Thanks!

03-29-2011, 04:58 PM   #47
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QuoteOriginally posted by philippe Quote
Well, H C-B was not discussing the optical qualities of lenses but reacted on a remark about the motion blur in some of his pictures and the lack of sharpness due to the use of the 'small format', rather rare at the time.
Actually, what he was trying to say is that the inspiration and the moment (decisive or not) and the image it generates is more important than the quest for technical perfection...
Believe me, I fully understand what he meant, and I basically agree, but that does not stop me from wanting the finest lenses that I can afford.
03-29-2011, 05:12 PM   #48
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The DA15 is very sharp wide open, but I also initially had some problems getting sharp photos.

What I traced it to was that in Av mode the shutter speed chosen can be too slow to prevent camera shake, let alone freeze subject movement. I've now greatly reduced my shooting of my DA15 & DA21 in Av mode, and tend to prefer Tv or manual modes so I can keep the shuter speed up 1/100 or faster (oh for TAv mode on my body )

There may be better solutions, like maybe if I could tell it to crank up ISO to compensate in Av mode and not drop the shutter below 1/100 for any lens, but on a K-x this doesn't seem possible.

Not saying that's definitely the problem, but that's my experience anyway.

Last edited by twitch; 03-29-2011 at 05:22 PM.
03-29-2011, 06:15 PM   #49
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QuoteOriginally posted by philippe Quote
Well, H C-B was not discussing the optical qualities of lenses but reacted on a remark about the motion blur in some of his pictures and the lack of sharpness due to the use of the 'small format', rather rare at the time.
Actually, what he was trying to say is that the inspiration and the moment (decisive or not) and the image it generates is more important than the quest for technical perfection...
Believe me, I fully understand what he meant, and I basically agree, but that does not stop me from wanting the best lenses that I can afford.

03-29-2011, 09:52 PM   #50
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Hmmm...my FA 77/1.8 is pretty sharp wide open. That being said, the first lens that came to my mind is the Zeiss Biotar 58/2 and related lenses (FSU Helios 44 series, for example). The design provides center sharpness even wide open at the expense, somewhat, of corner sharpness. On APS-C the crop provides fairly even performance across the field.

Now, I can almost hear the chorus of nays even as type this, but the proof of the pudding is in the eating. Wide open, when used with a hood, my Helios 44M is entirely equivalent to my FA 77/1.8 Limited.

Flickr: Helios 44M on fotostevia's photostream


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03-29-2011, 11:19 PM   #51
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I've never much encountered a lens that was not sharp wide open except for the Jupiter 9.
Most lenses are sharp wide open but not at its sharpest.
However, there are some lenses that seem to marry shallow DOF, contrast and adequate sharpness to give a sharper look.
03-30-2011, 04:55 AM   #52
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QuoteOriginally posted by pinholecam Quote
I've never much encountered a lens that was not sharp wide open except for the Jupiter 9.
All Pentax 50/1.4 lenses are soft wide open. I wouldn't call the 50/1.2 sharp wide open either.
03-30-2011, 05:14 AM   #53
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Due to the very thin DOF, it's hard to do something about these lenses.
Thin DOF and sharpness are just opposite properties.

Personally, I think this discussion is going to a dead end. How sharp is sharp enough? What is ones definition of sharpness? How wide open is fast enough? There are physical limitations, and there are personal preferences: optical properties, size, weight, price, availability, MF/AF.

03-30-2011, 05:25 AM   #54
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QuoteOriginally posted by hoanpham Quote
Due to the very thin DOF, it's hard to do something about these lenses.
Thin DOF and sharpness are just opposite properties.
Thin DOF just makes it harder to place the subject within the DOF. There is still a slice through space that is rendered with optimal sharpness (relative to the optical performance of the lens).

Very fast lenses often have quite a bit of spherical aberration wide open, preventing them from delivering very sharp images. This is not a problem of thin DOF.
03-30-2011, 05:26 AM   #55
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Sharp enough wide open?

QuoteOriginally posted by pinholecam Quote
I've never much encountered a lens that was not sharp wide open except for the Jupiter 9.
Most lenses are sharp wide open but not at its sharpest.
However, there are some lenses that seem to marry shallow DOF, contrast and adequate sharpness to give a sharper look.
I think you might avoid some flames if you'd replace "sharp" with "sharp enough".

Each lens has a particular sharpness (ie contrast at a particular resolution) wide open. Some lenses have more resolution wide open than other lenses.

So what? If lens A and lens B produce images that are equally sharp for the display does it matter which is the sharpest at some irrelevant extreme?

If you are going to rely on framing your photo in the viewfinder rather than cropping, the actual sharpness need is only that the lens be sharp enough at the display pixel level. It doesn't matter if the lens fails at resolutions smaller than the display pixel.

I like to have lenses that allow me to crop photos taken at low f-numbers but that doesn't necessarily mean that I can't take equally good photos with a lesser lens if I don't crop the images.
03-30-2011, 05:39 AM   #56
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QuoteOriginally posted by Class A Quote
Very fast lenses often have quite a bit of spherical aberration wide open, preventing them from delivering very sharp images.
The Leica noctilux 50mm f/0.95 ASPH is excepted from this, the Leica lens does not exhibit any of the "leica glow" or spherical abberation it's predecessor did*. I will have to do a side-by-side comparison some time, I'll want to borrow a voigtlander 50mm f/1.1 to make it a comprehensive comparison though.


*some aficionados actually say the correction of the spherical aberrations robs the Noctilux of it's character and i'm inclined to agree. the Leica-M 50mm f/0.95 ASPH renders things with the same absolute clarity that the slower 50mm f/1.4 does - but with significantly shallower DOF.

here is an image demonstrating the "glow" from the Leica-M Noctilux 50mm f/1.0 on the Leica M9 - also note that this is shot at infinity, and the resulting image is quite impressively sharp despite the glow.

Last edited by Digitalis; 05-20-2011 at 11:50 PM.
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