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01-27-2009, 02:04 PM   #1
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For you pixel peepers...

Middle of the winter -14C and house bound so l..

...compared my Tak 105, Sigma 105 macro, kit lens and FA 35.

All were taken at f/8, available light, tripod mounted, with lens shade, 2sec delay etc. Taken with a K20d set to the way I normally take pictures. Cropped to center portion of FF but no further PP. All represent best of three shot manual focus.

I know this crude methodology leaves much to be desired but I was just interested in seeing if there was any really stunning differences between the lens'.

1. full frame example showing the crop area of all the rest of the images.
2. Tak 105 crop
3. Sigma 105 macro crop
4. Tak 55 crop
5. kit lens (ver I) at 55mm crop
6. Fa 35 crop

Make what you want out of it.


Last edited by wildman; 01-29-2009 at 12:00 PM.
01-27-2009, 02:06 PM   #2
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FA 35 crop

Last edited by wildman; 01-29-2009 at 12:00 PM.
01-27-2009, 02:08 PM   #3
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one missing

one image appears missing so it is kind of hard to guess which.

ALso I assume all were done to give same image size, yes?
01-27-2009, 02:17 PM   #4
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QuoteOriginally posted by Lowell Goudge Quote
one image appears missing so it is kind of hard to guess which.

ALso I assume all were done to give same image size, yes?
The last one (FA 35) under a separate following post.

Yes camera was moved to give more or less same FOV.

01-27-2009, 02:20 PM   #5
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first comment, kit lens is worst but then again they usually are
01-27-2009, 02:25 PM   #6
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QuoteOriginally posted by Lowell Goudge Quote
first comment, kit lens is worst but then again they usually are
Yes a no-brainer
01-27-2009, 03:25 PM   #7
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Sigma seems sharpest in this
01-27-2009, 03:41 PM   #8
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Differences in color as well though I cannot see much difference between the Tak and the Sig. The kit may clearly have the softer focus but all colors are questionable as to which may be the truest - and why is everybody looking at me that way now?

01-27-2009, 05:04 PM   #9
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For the images posted does each display pixel map to the same number of sensor pixels?

Maybe it is just me but I can't see much difference in the resolution bars. I can discern the three horizontal bars at center 1 in all images, so that's not my measure of quality.

Rather, my impression of quality is fixed first by apparent sharpness of step (and corner) edges, like the upper right corner of the upper square.

Then my judgement seems to fall to background noise - maybe even the sharpness of the background noise. I know this sounds backwards, but the kit len's background is too smooth.

I'd be pleased to know what features others use to make quality judgements here.
01-27-2009, 05:13 PM   #10
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Interesting that, shot in Av mode, the kit lens not only picked the fastest shutter speed but also yielded the brightest exposure. I thought the conventional wisdom was that it "underexposed" relative to other lenses. But whether you measure by how the camera metered, or by the results obtained at a given fixed exposure setting, that would appear to be false on both counts in this test.
01-27-2009, 06:16 PM   #11
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Shoot in manual mode to keep the aperture and shutter speeds to be the same for all lenses. As it is, the slight differences in shutter speed means the images vary in brightness/contrast.
01-27-2009, 06:41 PM   #12
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QuoteOriginally posted by creampuff Quote
Shoot in manual mode to keep the aperture and shutter speeds to be the same for all lenses. As it is, the slight differences in shutter speed means the images vary in brightness/contrast.
That's a tough one, I don't think I've ever seen a pentax lens with t-stops on it, meaning that keeping aperture and shutter the same is going to show different exposures, e.g. tak vs. sigma, tak. vs. kit vs. fa35. They're all going to be different, and correcting with curves in postprocessing is going to alter contrast and brightness as well.

Correcting with shutter speed (as one would with t-stops when keeping the aperture the same) is the closest thing I can think of to keep things even. I do have to say, pixel peep all you like, but they're all fine lenses for what they are, and for their relative prices. I'd be happy with any of them and am with the 3 that I have.
01-27-2009, 10:33 PM   #13
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Even given the limitations of my little test I'm struck by how little difference there really is -

The Tak 105, Sigma 105 and the FA 35 are all close enough that I wouldn't lose any sleep over the difference.

I would have expected the Tak 55 to do relatively better than it did but who's to say what's going on with a 35 year old lens.

One the things I have learned since getting the Taks is how important ergonomics is to my way of shooting. I don't mind manual focus but I do miss not having auto diaphragm control. It really slows things up especially with the Taks having such narrow, stiff, out of the way and hard to read diaphragm rings. The same goes for the focus ring. If I do have to manual focus I much prefer the wider and lighter touch of both the Sigma and FA 35 focus rings. I like gear to get out of my way and allow me to concentrate on the image and not on the gear.
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