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Forum: Pentax SLR Lens Discussion
03-09-2013, 07:42 PM
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I just realized that the iris of my ST moves (like 1mm) when I pull focus, I haven't noticed it while shooting but I was checking the lens for dust earlier today and I realized it moves, and it fiels like something moves inside, just a tiny bit but it feels weird. That isn't right, right?
I made a video of it:
https://vimeo.com/61440379
password: test
I know it might look like an optical illusion but when you have the lens in your hands you actually feel something moving inside the lens(very subtle). Just double checking if that is normal (doesn't happen in my MF Nikon lenses) or I'm just getting too paranoid after finding the blue spot.
Thanks
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Forum: Pentax SLR Lens Discussion
03-09-2013, 05:06 PM
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Both lenses (RIkenon and ST) look very similar built wise, maybe they share design/coating and that's why they produce the bright spot... or not.
Thanks,
Ruben
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Forum: Pentax SLR Lens Discussion
03-09-2013, 10:57 AM
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Talking about coatings...Did you guys have any issues with yellowing? I know that 7 elements version, SMC and Super Multi Coated have thorium in their coating and that might provoke yellowing.
I was checking prices for 50mm SMC takumars in eBay and a few sellers said that they "UV treated the lens for yellow", is there a process (besides exposing the lens to sunlight for days) to treat the yellowing?
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Forum: Pentax SLR Lens Discussion
03-09-2013, 10:50 AM
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I believe you are right in the info you wrote but in the pic you posted your mark lenses wrong, the one on top is the 7 element SMC (red mark next to 4 is on the left, says MANUAL and AUTO) and the one below is the 8 elements (red mark on the right side of 4, and says M and A). You're right either way.
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Forum: Pentax SLR Lens Discussion
03-09-2013, 10:48 AM
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Thanks for the samples pics of both lenses. Which one do you like better on your 5D? I knoe that the 8 elements flares more but that's not an issue for me (as long as I can controlled the flare not like the sensor reflection issue I'm having).
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Forum: Pentax SLR Lens Discussion
03-09-2013, 10:41 AM
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I understand that its price is higher because it's a rare version, but for what I read in this forum and others everybody who owned the 8 elements and 7 elements (ST or SMC) liked much better the 8 element version than the 7 element, even keeping in mind that the SMC has 8 blades instead of 6. I might get a SMC copy from ebay but right now I can not spare 150-200 USD for a duplicate lens, I really want to buy the Volna-9 2.8 macro, I don't have a macro lens and I read pretty good things and I love how russian lenses look.
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Forum: Pentax SLR Lens Discussion
03-08-2013, 11:09 PM
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I'm going to try to test this same lens on a 5d mkIII, just curious to see it gets the same reflection. I read that the Super Takumar rear element actually passes the mount when focused to infinity inside the camera body(when the lens was on close focus I didn't see it), and that's what creates the reflection, I believe this won't happen with a 7 elements version or a SMC because the rear element doesn't go that far when focus to infinity.
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Forum: Pentax SLR Lens Discussion
03-08-2013, 09:12 PM
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Which one do you like better? Do they prone to flare (I don't know if you've tried the 8 elements version).
Thanks
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Forum: Pentax SLR Lens Discussion
03-08-2013, 08:34 PM
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Does anyone know if the 7 elements version or the SMC versions have this problem too? I did a lot of research to make sure I was buying the early 8 elements, legendary, 60's... blablabla version.
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Forum: Pentax SLR Lens Discussion
03-08-2013, 08:02 PM
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Thanks for the link, sounds extremely familiar (and disappointing). I was so exicted about this lens, I still love and I can just shot form f1.4 to f8, I bought to use it in low light situations, but it sucks that I can not use the entire f stops range...
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Forum: Pentax SLR Lens Discussion
03-08-2013, 07:55 PM
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Hi!
I used a hood (look at attached pic). I also forgot to mention that it's the 8-element version and the lens had a Quantary Multi-Coated UV Protector filter on (I tried with filter on and off and there was no difference. I know that the early 8 element version tends to flare, that's one of the reason why I bought since I shoot video and I love flares (controlled flares). But I was pointing down, it snowed but the day was grey, no sun at all, and I still got flare/glare or whatever that is.
Should've I bought the SMC version? I read that this version is supposed to be the best one.
Thanks for your quick reply!
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Forum: Pentax SLR Lens Discussion
03-08-2013, 06:57 PM
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Hello,
I recently bought a Asahi Super Takumar 50mm 1.4 (M42), after doing a lot of research and reading this forum, I decided for the non multicoated version. I'm very happy with the lens bokeh, how is built and how good is for pulling focus, so smooth... I got it from ebay so it's not mint, just a few dust specks that won't affect image quality.
I mainly shoot video, and while doing some test today form my window I realized that the lens (I hope is not my camera sensor) was producing a weird magenta/purple circle right in the middle of the frame. It usually produces one when it flares or pointing to a window or any very bright light source, but in this case I was pointing to the ground. I did the same shot with a 28-70mm Nikon AF-S 2.8 on 50mm and I couldn't see that magenta circle in it. I made a few more test and looks like that is more obvious in video mode than stills, but only happens with the Super Takumar.
Has anyone had a similar issue with this lens? The circle's color si very similar to the reflection's color that the lens make when you look straight through it. I was wondering if it is an internal reflection due to the M42-EOS adapter or something that this lens always does. Or maybe I got a bad copy of the lens, I don't know but is driving me crazy... I realized that is more obvious when shooting f8-f11, f8-f1.4 it's almost imperceptible.
I attached some screenshots of the effect/artifact/aberration/glare (I don't know how to call it). Stils are Super Takumar at f16,11,8,4and 1.4
NOTE: There is a soft focus effect in all the shots because the window I was shooting through had a screen that is in the foreground out of focus, and these are screen shots of video shot at 1/50, I have no complains about the lens sharpness.
Thanks you!
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