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Forum: Pentax SLR Lens Discussion
09-12-2020, 04:46 PM
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Another thing that I noticed is that the aperture blades doesn't affect the image till f4.5,
If I look inside the lens when I stopping it down they will activate but diaphragm is not clearly visible till f.4.5 (at the higher apertures it's closure remains behind a circular object in the lens).
Is that a normal behave of this lens?
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Forum: Pentax SLR Lens Discussion
09-11-2020, 08:47 AM
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Hi,I found on ebay a smc da21 limited at good price, from an user who is selling all his pentax lenses.
Since it was the only one da limited lens I was missing, and besides saving some money instead of buying a new hd (I like more the smc starbust than the hd, as well as in the 15ltd), I tried.As soon as I arrive I notice that the lens has a slight play, a matter of microns, in the body part of the lens, if I turn it I hear a very slight noise. (it is the barrel that comes out after the focus ring that "moves")I've read that is a common issue with 21 ltd.However, as it doesn't suffer from front back focus, it is sharp and the lenses do not seem misaligned to me, and that it is not easy to find a smc 21 from European sellers, at that price, I had decided not to complain, it has to make photo, after all.
But trying it against a bit extreme backlight, I noticed that it suffers from a noticeable flare, even the one with the circular halo which could be in some cases nice to see, but that I have not noticed in any other wide lens I have.It doesn't seem to disturb the contrast of the whole image, but it seems to me a notable artifact.
Is this the normal behavior of this lens, in your opinion? (I enclose photos both where the problem is present and where not, those with the sun were the morning sun between a light white haze so perhaps not exactly the ideal situation...)
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Forum: Troubleshooting and Beginner Help
06-25-2020, 07:39 AM
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I've send it back and take another copy of the lens...
which behave similarly to the first one (the serial n. is different )
It could be the case that I'm particularly unlucky, but I think that this lens have some generic error in the aperture calibration.
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Forum: Troubleshooting and Beginner Help
06-10-2020, 02:53 AM
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Watching inside at the aperture diaphragm blades of your irix lens have you noticed any difference between f2.8 and f3.2?
As I said, on my copy, blades activate at F3.2, but so little that they are not visibile, and in manual mode the exposure is identical with f2. 8 or f3.2
My 100wr macro doesn't act like this f3.2 is darker than f2.8 and I can see the aperture blades.
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Forum: Troubleshooting and Beginner Help
06-09-2020, 12:14 PM
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@pepperberry farm;
just one thing now for certainty / curiosity: trying with optical preview button, aperture/diaphragm blades of your lens behave differently compared to the photos I posted above? (at f.3.5 close just a little and a f3.2 is virtually the same that at f2.8?(no blades are visible?(picture show 2.8, 3.5, 4.0, 5.6)
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Forum: Troubleshooting and Beginner Help
06-09-2020, 06:36 AM
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I think that if in all Irix 150 lenses at F3.2 the blades have activated but them are still invisible and at F3.5 & f.4.0 they appear like in the picture above, as it happens to me, maybe it is something "wrong" in the project, at least in K mount, but I think it's a bit strange thing for a 2018 project lens & I think it would make sense to point this out to irix.
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Forum: Troubleshooting and Beginner Help
06-08-2020, 12:46 PM
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Has anyone tried to check if the diaphragm blades behave as in the picturea above?
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Forum: Troubleshooting and Beginner Help
06-07-2020, 05:17 PM
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I find that is overexpose a little everytime except when at f.2.8.
This because the diaphragm close not so much to reach the selected F, but less, and the camera calculate exposition with the selected F stop.
F2.8 should be need half time than an F.4.0 to reach the same exposure and with IRIX 150 lens I need to set F5.6 to reach this.
I noticed it because shooting at f.3.5 the camera I had brighter images than at f.2.8, (the camera correctly raised the ISO).
So I tried in manual mode, there is no difference in the image between f 2.8 and f.3.5
I attach diaphragm blade pics at 2.8 (none) 3.5 (just a little) F4.0 and F5.6. (at F3.2 blades aren't visible yet!)
If you have any minutes to spend for it, try to check if is the same for you
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Forum: Troubleshooting and Beginner Help
06-07-2020, 04:17 PM
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The sovraexposure is quite easy to compensate with -0,5 -0,7, the optic is fine, I don't want to send It back with the risk of receiving a lens with the same problem.
I think this could be a problem that could have gone unnoticed by some users and I would like to be sure that this isn't a problem of all the IRIX 150 (pentax) instead of my one, before sending it back.
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Forum: Pentax Price Watch
06-07-2020, 11:33 AM
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So I take it, and I confirm that is very good, at least stopped down, (infinity focus at F2.8, I know it isn't the goal of this lens, is quite soft)
However I have find an issue, that I've already posted in the troubleshooting thread and I have to decide whether to send it back
(F value does not match with the camera selection, diaphragm works, but shooting at f.2.8, f.3.2 or f3.5 is pratically the same,even with optical preview button, watching at the diaphragm inside the lens and at F.3.2 it close almost nothing, at f3.5 it close just a little and however not quite to influence the picture.
I've tried to obtain tha same exposition as it should be with the same ISO at 1/320 F2.8 and 1/160 F4.0 , but I've to stop down to F5.6 (1/160) to achieve the same result.
This happen on KP & K30.
If is it "normal behave" for this lens I would avoid sending back and waiting for another with the same problem)
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Forum: Troubleshooting and Beginner Help
06-07-2020, 11:10 AM
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Your lens, on KP, shown the same problem I report?
---------- Post added 06-07-20 at 08:44 PM ----------
Diaphragm works but (for example) if I put F5.6 it is an F4, but the camera calculate the correct exposure for 5.6, so the picture goes overexposed.
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Forum: Troubleshooting and Beginner Help
06-07-2020, 10:40 AM
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No, my problem is not the same
I'got the KP & K30, and the control works, but I notice that F is not the real F selected in the camera control.
I've to understand if all the irix 150 macro lens has an real F value that doesn't match with the F shown and selected by the camera control (at least on kp & k30), or I've to send the lens back to the dealer (it's new, but I'don't wont to wait for another identical lens with the same issue)
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Forum: Troubleshooting and Beginner Help
06-07-2020, 09:00 AM
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Hi, is it normal that shooting at f.2.8, f.3.2 or f3.5 is pratically the same?
I try even with optical preview button, watching at the diaphragm inside the lens and at F.3.2 it close almost nothing, at f3.5 it close just a little and however not quite to influence the picture.
However the camera calculates exposition and it goes overexposed comparing it with the F.2.8 shots
I've tried to obtain tha same exposition as it should be with the same ISO at 1/320 F2.8 and 1/160 F4.0 , but I've to stop down to F5.6 (1/160) to achieve the same result.
I try with the KP and the K30 and it is the same.
It's a problem on APS-C sensor (but it' wouldn't), all the irix works like this, or I've a problem with th my copy of the lens?
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Forum: Pentax Price Watch
06-01-2020, 01:39 PM
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Hi, does it works fine on pentax kp?
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Forum: Pentax DSLR Discussion
08-24-2019, 01:21 PM
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Hi everybody,
After two week of KP, and many shots, I can't find any difference between the two settings (AWB & MAWB)... at least on the KP lcd (I'm on holiday and I can't watch them on a monitor) ...(I take the picture in daylight or shadow or under a tungsten light in a room...not at night) ...
I run the last update firmware
Is multi auto White balance effective only in certains situations or is my camera that have some bug?
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Forum: Pentax SLR Lens Discussion
07-26-2017, 02:53 PM
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I'm going to buy the 55-300 PLM on my k-30 (I've update my camera with k-50 firmware)
Is it possible to use this lens with the 1.4x pentax rear converter? (It seems to me I've red somewhere that it shouldn't work)
However, if it works, do you think that image quality at max focal lenght is still good? (adapter with 55-300 plm and also with 55-300 wr)
Thank You
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Forum: Pentax K-30 & K-50
07-26-2017, 09:34 AM
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Do you find that using an external flash?
Using my k30 integrated flash, works fine.
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Forum: Pentax DSLR Discussion
12-09-2015, 05:41 AM
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Ok, so, for people like Class A who are against the removal of the AA filter, found that the AA simulation system introduced by Pentax with the K-3 works fine?
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Forum: Pentax DSLR Discussion
12-05-2015, 07:06 AM
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Why does the flash can produce problems without aa?
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Forum: Pentax DSLR Discussion
12-04-2015, 03:50 PM
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Hi,
I would like to know whether is the difference between the same sensor one with and one without antialiasing filter evident, especially in macro photography?
Thank you
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Forum: Pentax DSLR Discussion
12-03-2015, 01:55 AM
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Hi,
does anyone do this upgrade?
I've read that new sensor had lost something in shadow recovery but is there anyone that doing the upgrade from k30 - k5 sensor to k3 's one is no longer able to bring out the shadows as before from a raw file? Or is it a negligible difference?
I would like to know if I will get a real improvement in image quality without the AA filter, especially in macro.
Thank You
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Forum: Pentax SLR Lens Discussion
12-06-2012, 02:22 AM
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Thank You.
Wich is better instead for standars photo? (eg. portrait, not macro)
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Forum: Pentax SLR Lens Discussion
12-05-2012, 04:12 PM
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Hi everybody...
Between one used (perfect condition) Pentax D-FA 100mm WR macro and a new Tamron 90mm Macro for the same price, which one would you choose and why?
Thank You
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Forum: Post Your Photos!
11-20-2012, 03:06 AM
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