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Forum: Pentax SLR Lens Discussion
09-17-2019, 12:02 PM
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Thanks again for the advice. Sent the lens back which was not a problem and got a full refund. Found another used one for just £20 more (£349 inc free delivery). What a difference! Much sharper and consistently sharp across the frame. Bit softer at the edges compared to the centre at maximum aperture but that's to be expected but not really noticeable at normal image viewing distances. Far less CA at the edges than the first example - in fact hardly any at all. The performance of this one seems to match the excellent reviews it has received. Problem solved!
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Forum: Pentax SLR Lens Discussion
09-10-2019, 08:51 AM
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Bad weather meant that wall photos were not practical - I know the K1 is waterproof but ....
So used a lens test chart which is A1 in size. Spent ages making sure the camera was level in both directions and exactly in the middle of the test chart suing huge set square tape measures etc to that it was exactly parallel to the chart.
The result was that there was quite a difference in clarity between the bottom left (1st image), bottom right (2nd image), top left (4th image) and top right (5th image). Fine focus set to +10 to get the centre focused as well as possible (3rd image)
As a result of this test decided to send the lens back and will look for another.
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Forum: Pentax SLR Lens Discussion
09-09-2019, 12:19 AM
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Thanks. I'll try a few more as advised by you and post them soon.
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Forum: Pentax SLR Lens Discussion
09-08-2019, 05:35 AM
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Thanks for the feedback.
As suggested tried a few test shots and results attached. Hopefully the filenames explain the camera settings. (focal length +fine focus correction). All images taken at either f3.5 for 28mm and F5.6 for 105mm. 100 ISO and shutter speeds of 1/1250s or about 1/650s. Wall photos at 28mm +0 (image 1), edge a lot worse than centre but (2) 28mm +10 (image 2), centre gets worse, edge gets better. 105mm - centre and edge both improve with fine focus on +10 (image 4) rather than 0 (image 3). Images are all raw files lightened a bit and saved as jpegs. No sharpening or other changes in photoshop. All full frame images.
Just to clarify, I am not one of these pixel peepers, its just that the images from the first outing with the lens were really disappointing and not what I expected from a lens with such good reviews. I have looked at some sample photos (high res) on various review sites and the detail at the edges is amazing and very little different from the centre but seem to be much better than my copy.
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Forum: Pentax SLR Lens Discussion
09-07-2019, 09:04 AM
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Just bought a used Pentax 28-105mm DFA. Looks in very good condition. This has had some amazing reviews in terms of good image quality and low CA. Took the lens out for a the first time yesterday (on a Pentax K1) and was a bit disappointed with the images sharpness particularly towards the edge of the frame and the large amount of CA, again at the edges of the image. Played around with the K1 focus adjustment and when on +10 the focusing is a lot better but still back focuses a bit. Also tried it on a K3 and similar back focus but correction of +5 sorted it out. Don't think it is the K1 at fault as most other lenses have no correction or very slight (for sigma 70-200 Mk II). Has anyone else had similar image quality issues?
Lens has a guarantee so should be able to send it back if it proves to be a bit of a "duff" copy.
Thanks
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Forum: Pentax K-1 & K-1 II
09-07-2017, 06:26 AM
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Hi.
I bought a Pentax K-1 a week ago. I had a sigma 24-70 f2.8 HSM and Sigma 70-200 II Macro HSM, both bought second hand on Ebay. They both worked well on my Pentax K3 except for the 70-200 in live view - a problem I had read about on various forums but wasn't really bothered. I was also aware of the mounting problem and possibility of scratching the K-1 body. I contacted Sigma servicing UK about the mount modification. One lens was posted off on Thursday 31st August and the other the following day. I was told that the turn around was 7 days. Communication was excellent, I was informed when the lenses arrived and when they were dispatched. Both lenses arrive home on Wednesday 6th September, mounts modified, firmware upgraded and they both work perfectly on the K-1 (and K-3 in live view). The only cost was some packaging materials and under £20 postage in total. The service from Sigma (UK) was first class and can not be faulted. Really pleased. (To add to the satisfaction, whilst the lenses were away, I downloaded the firmware upgrade for my Metz AF58 mk1 and it also now works perfectly.)
Just wanted to publicly praise the Sigma Service Centre (UK)-great service and the modifications were free of charge.
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Forum: Pentax K-1 & K-1 II
08-31-2017, 01:54 PM
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Hi. I am new to the forum but not Pentax cameras. I bought an MX back in 1979 added a second hand KX (film) and a couple of LXs, all of which I still have and use (except KX). Then came autofocus (MZ-3 and MZ-s both still in use) and finally digital (K10d and K5 part exchanged for K3). Took the plunge a few days ago and bought a K1 -awesome. That's the history, now the question.
Changing from a selected ISO to Auto ISO is straight forward and same as K3 - press ISO followed by green button. However, is there a quick way of changing back to the previously selected ISO without having to press the ISO button and twiddle the rear e-dial? It was a small irritation on the K3 but as high ISO values of K1 seems so much more useable, it obviously can take a bit longer to adjust from a higher ISO back to my usual lower value of about 200.
Thanks
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