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08-20-2007, 03:25 PM   #16
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I'll start by saying that I don't know much about testing lenses. But wouldn't you want to compare the two lenses on the same playing field. If you tested the DA 50-200 at the 50mm setting f4.0 and 1/13th sec, then you would want to test the FA 50mm lens set at f4.0 and 1/13th sec. under the same conditions. That way you can compare apple to apples. Then I might even try f5.6, f8, and f11 to see what I could get at those settings. Just some thoughts, good luck with your decision.

By the way, I think you have taken some really wonderful pictures with both lenses.

Oh, one more thing. I would also try to get a faster shutter speed, or use a tripod with the mirror lockup to eliminate the possibility of camera shake issues. Good luck!

08-20-2007, 04:50 PM   #17
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Very good point

Fritz, thank you for the suggestion. I have not thought about that. But I thought f/2.0 in FA 50 f/1.4 is the sweet spot many people has suggested and that is reason that I try to see if my lens is lemon or not. But your suggestion is very valid on comparing two lens on similar setting.

Much thanks,
Hin
08-22-2007, 04:09 PM   #18
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Return lens for an exchange

I finally gave in and called BeachCamera for an exchange. It is very nice that BeachCamera offers me the RMA for an exchange. I hate returning stuff but over 10 days of testing, I can't conclude if my copy is normal. I like everything about this lens but I find my copy to be too soft even at f/4.0 in outdoor and certainly for my case f/2.0 is extremely soft for indoor in my test shots. When I view at 100% crop, I see edges not as sharp as what I am used to with my kit's len and DA 50-200. It is still possible that I have user errors in all of my testings but I just can't figure out what I did wrong in all the pictures taken with the new lens. Thanks to everyone for the comments and suggestions.
08-24-2007, 05:56 AM   #19
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Hmm

My 2 cents:

I don't think there is anything wrong with your FA 50. It seems that what you consider "softness" is simply the lens's extremely shallow DOF, especially when you're shooting subjects at a very close distance (as the 'test' shots seem to indicate -- unless they're cropped (sorry; didn't read that carefully)). The DOF is paper thin at f/1.4, and still very thin at f/2 (and even f/2.8, in my experience), at relatively close distances. Thus, using the DA 50-200 (at 50mm) at f/4 will obviously have a larger DOF than using the FA 50 at 1.4 or 2, and hence is not a good comparison.

But if there is a problem with the lens, my guess is that it is front- or back- focusing (rather than "softness" -- your images look sharp enough to me, if one looks to the right spots). I've found that, every so often, my FA 50 front-focuses. (I'm not sure what causes this -- sensor cleaning, bumps, too many lens changes?). To cure this problem, I found a very helpful entry on dpreview.com's pentax forum regarding the K100's "debug" mode. Using the debug mode, I've been able to cure the front-focus problem so that the lens focuses perfectly (though, as said, I've had to do this a few times over the last couple of months).

Additionally, I've also found (and have read) that the FA 50 (and perhaps other lenses as well) may focus perfectly in daylight conditions, but may front- or back- focus under incandescent light.

Anyway, good luck with your next 50.

08-24-2007, 06:10 AM   #20
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Havent used mine as yet but now i'm glad i did purchase it, no regrets from the looks of those pics ..
Awaiting a lens hood and filters before i take it ofr walkies..
Doin the right thing???....
Cheers
08-24-2007, 06:38 AM   #21
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Your photos look fine to me. It is of course not so easy to tell with resized web shots, but still I can't see a major problem with softness.

At the risk of being told off for measurebating and pixel-peeping... it is possible for a lens to have front or back focus issues. Even with the best will in the world and good quality control, things like this cannot be totally avoided all the time. I have had a lens on which the focus was totally out, and can confirm that this was not "user error"... however that was a third-party lens... I have only ever had slight back-focus on a Pentax lens.

Anyway I believe - I cannot say for certain but I think - that you are not having problems with front or back focus. In your "star-on-wall" test shots, the focus seems to be exactly where it should be.
08-24-2007, 06:40 AM   #22
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QuoteOriginally posted by Papou Quote
Havent used mine as yet but now i'm glad i did purchase it, no regrets from the looks of those pics ..
Awaiting a lens hood and filters before i take it ofr walkies..
Doin the right thing???....
Cheers
No no no...

Allowing a newly bought Pentax lens to gather dust, even for a day, is very very wrong
08-24-2007, 06:48 AM   #23
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Oh, if only that red warning construction code wasn't there in that one shot... !

I too am so happy I purchased one recently.

If you can see the Milky Way where you live, you can take fantastic star shots with it. Try this, with -NO- stray light around... (else you get a color cast to the frame)

1) focus on manual, set to infinity
2) WB set to daylight
3) Shutter set to max (so unhappy its max is 30 seconds)
4) ISO set to 400
5) Shutter release set to IR (if you have the IR remote)
6) flash off (do I need to say that? )
7) Lay the camera on its back, and prop it at an angle if the milky say isn't overhead (! if you're putting it on a rock, but cloth underneath ... else you'll scratch the screen like I did! )
8) Use the IR remote to take the pic.

edit) duh, I forgot to include/mention the obvious, set aperture to f/1.4.

You can shoot multiples and stitch them together even. When you zoom in, you'll see the motion of all the stars within the 30 second timeframe; 1/8th of a degree. If you don't want the motion, reduce the shutter length.


Last edited by m8o; 08-24-2007 at 11:27 AM.
08-24-2007, 08:09 PM   #24
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Thanks everyone...

Thank you everyone for the input. It will take me a while to digest all the valuable inputs. I am very grateful for all the pointers and opinions. I will reply later on after some needed quality time with my younger boy who is sick from asthma today. I will update soon. Thanks everyone.

Hin
08-27-2007, 08:55 PM   #25
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I am no expert but I remember reading that at the lowest F-stops this lens is not performing in its sweet spot. Also, the focus and sharpness are going to be at a very specific point and everything that's even slightly more foreground or background (even as much as a nose vs. an eye) will be out of focus given the sensitivity of the f-stop. Maybe try dialing the aperture the other direction a little bit to bring more of the scene surroundings a little bit sharper.

keep in mind this is a very amateur description of something I read a while ago on this same forum. Maybe totally off base...

I'm really enjoying this lens. It took some getting used to, but the results have been great for me.

Mjz
08-28-2007, 07:38 AM   #26
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I think you are EXACTLY on the mark! When you're at f/1.4 and up close, the DOF is VERY shallow. I think Hinman's lens is working fine, he just has to get experience using a REALLY fast lens.

About the only time I use my 50mm wide open is in VERY low light. I find that even at f/2.8 the DOF is sufficiently shallow to get a nice blurred background (along with much better sharpness/contrast). So unless you need f/1.4 to get 1/30s @ISO1600 (yep, been there!), stop it down

QuoteOriginally posted by sillyzippy Quote
I am no expert but I remember reading that at the lowest F-stops this lens is not performing in its sweet spot. Also, the focus and sharpness are going to be at a very specific point and everything that's even slightly more foreground or background (even as much as a nose vs. an eye) will be out of focus given the sensitivity of the f-stop. Maybe try dialing the aperture the other direction a little bit to bring more of the scene surroundings a little bit sharper.

keep in mind this is a very amateur description of something I read a while ago on this same forum. Maybe totally off base...

I'm really enjoying this lens. It took some getting used to, but the results have been great for me.

Mjz
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