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05-04-2009, 07:04 PM   #46
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From reading a bunch of these threads I think it really comes down to one question... do you need SDM? If you do get the Pentax, if you don't save some money and get the Sigma.

I have the Sigma and I think it is a great lens, but I've never used the Pentax so I can't compare.



John

05-04-2009, 07:07 PM   #47
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QuoteOriginally posted by Hythloday Quote
I am sorry to say that you did not test lenses, but which lens behaved best in artificial light. Clearly the Sigma focuses better in artificial light. When doing a test you should exclude all possible influences. My DA12-24mm always misfocuses in artificial light but outside it hardly misfocuses.
Unless you think window light is artificial light, then yes

Actually I don't really care much about this kind of pixel peeping test. The test I did was per request of my friends.

I used both lenses for quite a while, and I know which one suits me better. I wouldn't say which one is a better one (to me) w/o actually having used them both
05-04-2009, 07:11 PM   #48
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QuoteOriginally posted by panoguy Quote
For asdf, I guess it was. Aside from blind fanboy-ism, I have no idea why he insults anyone who doesn't agree that the DA 17-70 is "the hand of God made of glass and plastic."

Of course, the stunning images and youtube videos he shows prove he isn't just a measurebater.
Wow, I now have a stalker. Awesome.

QuoteOriginally posted by creampuff:
Was that dumbass remark even necessary?
That's plurium interrogationum.
05-04-2009, 10:58 PM   #49
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QuoteOriginally posted by frank Quote
Actually I don't really care much about this kind of pixel peeping test. The test I did was per request of my friends.
Then don't do it and tell your friend you're not interested. You posted 8 completely irrelevant, out of focus crops. My f/4 Pentax crop looks sharper than your f/5.6 Sigma one. If your shot is sharper at f/16 than at f/8, then you know you haven't focused right--your f/16 shot should be softer because of diffraction. Scroll down to the crops in the review below (although the problems with the review below can be numerous):

Pentax DA* 300mm f/4 Lens Review - Digital Camera Forums and Discussion


Last edited by asdf; 05-04-2009 at 11:13 PM.
05-04-2009, 11:41 PM   #50
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QuoteOriginally posted by asdf Quote
Then don't do it and tell your friend you're not interested. You posted 8 completely irrelevant, out of focus crops. My f/4 Pentax crop looks sharper than your f/5.6 Sigma one. If your shot is sharper at f/16 than at f/8, then you know you haven't focused right--your f/16 shot should be softer because of diffraction. Scroll down to the crops in the review below (although the problems with the review below can be numerous):

Pentax DA* 300mm f/4 Lens Review - Digital Camera Forums and Discussion
I used AF for all the testing shots. K20D camera on tripod, cable release w/ 2 second mirror up. If the photos are out of focus, it's either the camera or the lens or both. What I did was zooming and pressing the release button on the cable. When using a lens like these 17-70s, I don't care about manual focusing.

If you think my testing results are completely irrelevant, that's okay. I'm not posting it for you but for the TS. Just sharing my own experience, that's all.

And enjoy using your perfect DA 17-70
05-04-2009, 11:47 PM   #51
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It will be a looong time before I spend money on another lens with SDM.


But that is just me.
05-04-2009, 11:48 PM   #52
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QuoteOriginally posted by frank Quote
Just sharing my own experience, that's all.
I hope I'm contributing to the discussion by pointing out--what I see as--flaws in your testing. I hope you don't take it personally.

QuoteQuote:
And enjoy using your perfect DA 17-70
Yes, it's the "L" version sent to me by Ned Bunnell himself.
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05-05-2009, 03:01 AM   #53
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QuoteOriginally posted by asdf Quote
Then don't do it and tell your friend you're not interested. You posted 8 completely irrelevant, out of focus crops. My f/4 Pentax crop looks sharper than your f/5.6 Sigma one. If your shot is sharper at f/16 than at f/8, then you know you haven't focused right--your f/16 shot should be softer because of diffraction. Scroll down to the crops in the review below (although the problems with the review below can be numerous):

Pentax DA* 300mm f/4 Lens Review - Digital Camera Forums and Discussion
Who the hell gives you the right to tell people what they ought or ought not to do? So your copy of the lens is sharp, well good for you... but to say that another member posted completely irrelevant, out of focus crops is uncalled for.

You can like the gear that you have, but you don't have to be a flaming obnoxious fanboy by putting others down... and if you didn't know, frank is no wet-behind-the-ears newbie. He is probably one of the most experienced Pentax users around, so it would be good to accord others due courtesy... and less of the so obvious bragging

05-05-2009, 07:09 AM   #54
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QuoteOriginally posted by frank Quote
I used AF for all the testing shots. K20D camera on tripod, cable release w/ 2 second mirror up. If the photos are out of focus, it's either the camera or the lens or both. What I did was zooming and pressing the release button on the cable. When using a lens like these 17-70s, I don't care about manual focusing.

If you think my testing results are completely irrelevant, that's okay. I'm not posting it for you but for the TS. Just sharing my own experience, that's all.

And enjoy using your perfect DA 17-70
I am assuming from your statement "If the photos are out of focus, it's either the camera or the lens or both" that you dd not calibrate the lenses to the body. I have two K20D bodies and 5 Pentax lenses. Out of the 10 possible lens/body combinations that that gives me, there is only 1 that does not require a focus correction. One body FF slightly, the other has BF and the lenses vary as well. Two lenses require the same adjustment, the other three each need different amounts of adjustment. The point is that the chances of getting a lens that is perfectly matched to your body is pretty slim. The worst FA J series lens made would appear sharper than the best copy of a 31 ltd if at the default settings the FA J lens was focusing better than the 31. I don't mean to pile on here, but the only thing that using auto focus for a resolution test without first calibrating the lens to the body does is tell you which lens is more closely matched to your camera at the default correction of zero.

Last edited by Parallax; 05-05-2009 at 08:07 AM.
05-05-2009, 08:04 AM   #55
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QuoteOriginally posted by Parallax Quote
I am assuming from your statement "If the photos are out of focus, it's either the camera or the lens or both" that you dd not calibrate the lenses to the body. I have two K20D bodies and 5 Pentax lenses. Out of the 10 possible lens/body combinations that that gives me, there is only 1 that does not require a focus correction. One body FF slightly, the other has BF. The point is that the chances of getting a lens that is perfectly matched to your body is pretty slim. The worst FA J series lens made would appear sharper than the best copy of a 31 ltd if at the default settings the FA J lens was focusing better than the 31. I don't mean to pile on here, but the only thing that using auto focus for a resolution test without first calibrating the lens to the body does is tell you which lens is more closely matched to your camera at the default correction of zero.

Actually I did some AF adjustment on both lenses before I did the test. The Sigma was plus 5, which is a compromised value to average from the 17mm to 70mm end. I've done the same for the DA 1770 (and DA*1650, FA*2870 as well). Being a zoom lens, I can only choose a value which has the best average AF accuracy (to my eyes of course). It's a lot easier to do AF adjustment for a prime lens

As I said above, I don't really just rely on the testing results alone. I also use the lenses for actual shooting, during which I did feel I like the Sigma 1770 better.
05-05-2009, 08:18 AM   #56
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QuoteOriginally posted by frank Quote
..........................It's a lot easier to do AF adjustment for a prime lens
.................................
Amen to that! I have also found that the larger the max aperture, the easier it is to calibrate. At f4 that pesky DOF thing really starts to get in the way of making a critical assessment.

QuoteQuote:
I also use the lenses for actual shooting.........
Well that's a pretty radical approach, don't you think?

Last edited by Parallax; 05-05-2009 at 09:24 AM.
05-05-2009, 09:46 AM   #57
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I happen to have two practically identical pictures. One is taken with a Pentax K100D Super and the Sigma 17-70mm anf the other one is taken with a Pentax K200D and the DA17-70mm. Both are taken at aperture f/8 and 23mm. The difference in colour is also due to the difference in sensors and the time of the year. One was taken in August 2008 and the other one in April 2009.



05-05-2009, 10:22 AM   #58
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Hi all,

I'm a big lurker on these forums but then I saw this thread and thought I would make a contribution!

I have that Pentax 17mm-70mm f/4 and have used and tested it extensively. It's a great lens, it works well for landscape, portraiture and as a walk-about lens. I would be reluctant to use it for portraiture in low-light conditions, for that I would always use my 50mm f1.4. However I felt that I would contribute on some of the criticisms of the lens to clear up a few things.

Out-of-the-box, the autofocus doesn't do a great job. I first noticed it when taking shots at 70mm f/4 was everything seemed "soft" (consistent with the reviews of the lens). After a lot of testing at f/4, it was apparent that the AF wasn't getting the focusing correct. In order to get a good sharp picture at f/4, I had to go into the custom menu on my K20D and set it to around +5. I took many photos of the front of a book (my missus thought I was mad!) at each autofocus adjustment step and settled on +5. It's a superb lens, the SDM was great for a wedding I photographed recently.

Here are a few of my shots with this lens (the exif info may not be correct, I noticed it recorded the wrong focal length, need to check that out).

http://img154.imageshack.us/img154/7625/igp3706.jpg

http://img503.imageshack.us/img503/817/igp3708.jpg

http://img503.imageshack.us/img503/6859/igp3734.jpg

I don't care what a lens review tells me; I'm very happy with the sharpness, colour and contrast this lens delivers (besides, Photozone gave this lens a big thumbs up). Just make sure you spend time calibrating your autofocus for f/4 and you won't be disappointed.

If anyone wants any particular test shots at particular settings, let me know!
05-05-2009, 07:10 PM   #59
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...this thread popping up is great, I just sold my 18-55 kit and 50-200 and looking for something with more range than the kit lens.

It seems very hard to decide.
I'm leaning towards the Sigma because of price and macro-feature.
I'll probably get a DA 55-300 later

Last edited by skydragoness; 05-05-2009 at 07:18 PM.
05-06-2009, 07:27 AM   #60
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QuoteOriginally posted by skydragoness Quote
It seems very hard to decide.
Is is simple enough because you cannot go wrong with either lens.
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