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Forum: Pentax SLR Lens Discussion 06-18-2019, 02:15 PM  
Is this acceptable for a 20-40, or should I send it for reparation?
Posted By superdave
Replies: 19
Views: 1,237
I owned two copies of this lens and I was also annoyed by blurry edges, especially at 40mm. I do not have the lens anymore but something you can try is to focus somewhere between the center and the sides to see if edges become sharp, for example on one of the vertical third line. This is how I am doing with 11-18 which also have blurry sides if I focus on the center. Please tell us it this focusing trick work with 20-40 and produce sharp edges.

In regard to center sharpness, 20-40 is good but not excellent, this is normal I think. However it has a very pleasant bokeh and impressive flare resistance.
Forum: Pentax SLR Lens Discussion 05-21-2019, 10:55 AM  
HD PENTAX-DA* 11-18mm F2.8 review?
Posted By superdave
Replies: 26
Views: 1,640
I can't see any reason why it wouldn't fit?

Personally, instead of purchasing the Lee 82mm ring which was expensive, I gave a try to a new filter holder: the Kase K8 which comes with a magnetic polarizer and several adapter rings, for 120€. I didn't used it a lot for the moment but it does the job.

If you own the Lee polarizing filter however, the less expensive is to buy the 82mm ring.
Forum: Pentax SLR Lens Discussion 05-16-2019, 02:39 AM  
16-85mm vs 28-105mm on APS-C
Posted By superdave
Replies: 19
Views: 979
Wow, thank you for the samples!

I looked at them carrefully and I think I may give a new try to the 16-85mm. I rank it 2nd on your samples, with 31Ltd 1st but it is too expensive for me. The left side of the image look a little softer than the right side, but by a hair.

After a fresh look at my own samples, I think that my copy was a little misaligned with the right side softer than normal on the wide end, and the left side softer on the long end. I was a little disapointed by edge quality when I tested the lens, but after having tested more lenses which weren't better, I think that my judgment was altered by the sigma 18-35 that I tested just before, and 16-85mm is above the average. I still not like the edge quality at 16mm, but now that I own the 11-18, I can live with that. At 24mm f/8 edge are better than my old 12-24mm, so not bad finally. At 35mm it look worse than at 24mm, but maybe because of a misalignment. At 50 and 70, the lens is not as good as my 50/1.8 and 70Ltd however...

---------- Post added 16-05-19 at 11:44 ----------



I won't say that, or may be you didn't looked at the good image.
18-135 is the crapiest, sigma 30 is a joke for a prime, 18-55 is a kit lens, 16-50 is not as good as 16-85 (on the right side, but as good on the left side), 31 Ltd is very good!

Thanks for sharing samples, however I cannot see the quality on resized image.
Forum: Pentax SLR Lens Discussion 05-15-2019, 07:40 AM  
16-85mm vs 28-105mm on APS-C
Posted By superdave
Replies: 19
Views: 979
I read those review too, but I find ePHOTOzine give very good score to all the lenses... For example, there are many lenses with 4.5 stars with crappy IQ in the samples. Moreover result is often very different in the field than on the review bench.

In regards to the gap between 16 and 28, it doesn't matter as long as the IQ is great. At the moment, I have a big gap between my 11-18 and the 50/1.8... and I am looking for a zoom, or a prime between 18 and 50 with excellent edge performances.

---------- Post added 15-05-19 at 16:51 ----------



I will look for an example when I get home.

I tested many lenses to fill my gap between 18 and 50mm, and I look for a lens with similar performance than my current lenses (11-18, 50/1.8 and 70mm Ltd).

I tested: 20-40 Ltd (2 copies), 35/2.4 (bad copy maybe?), 16-85mm, sigma 17-70 (decentered), sigma 18-35 (3 copies), 40 Ltd, 35 Macro Ltd, Tamron 17-50. The lens with better performance was the Sigma 18-35 (really stellar), but all of the 3 copies I tried had a different problem...

I also tested prime such as 40 Ltd and 35 Ltd. Those lenses were good in daylight, but for night cityscapes, the focus accuracy was very poor and most of my photos were out of focus (even in LiveView).

Samples of the 28-105 looks good on ephotozine.com, but I am a little tired to purchase and send back lenses...

---------- Post added 15-05-19 at 16:52 ----------



Sure, may be I had a bad copy, I tried only one copy and I would not have ranked my copy 4 or 4.5 stars.

---------- Post added 15-05-19 at 16:53 ----------



Thanks and lol. Any chance you got landscape samples around 28mm and 35mm f/8 with your 28-105?

---------- Post added 15-05-19 at 16:57 ----------



I will upload few samples when I got home, and ask here if the IQ is normal or not. May be I am asking to much for a 600€ lens.
Forum: Pentax SLR Lens Discussion 05-15-2019, 03:22 AM  
16-85mm vs 28-105mm on APS-C
Posted By superdave
Replies: 19
Views: 979
Hi all,

I tried 16-85 on my K-3 few months ago and was a little disapointed by its edge performance.
I wondering if 28-105 would perform better on APS-C in regards to edges?
Does anyone here have compared 16-85mm and 28-105mm on a K-3 or KP and have comparison shots?

Thank you.
Forum: Pentax SLR Lens Discussion 05-09-2019, 11:05 PM  
HD PENTAX-DA* 11-18mm F2.8 review?
Posted By superdave
Replies: 26
Views: 1,640
The are nice tutorials from Mike Kelley, an architectural photographer, on fstoppers.com. He is using 24mm tilt shift lens for more than 90% of it's work, so may be the Rokinon/Samyang 24mm T/S lens is a good option too if you only do real estate photography.
Forum: Pentax SLR Lens Discussion 05-08-2019, 11:12 PM  
HD PENTAX-DA* 11-18mm F2.8 review?
Posted By superdave
Replies: 26
Views: 1,640
I really like this lens, and it is definitely better than my old Pentax 12-24. I was a little worried with edge performance at the beginning, but I found an article called "Finding the best average focus point" (link below) and now I focus a little off-center and my edges are very sharp. It is because of field curvature.

I just wait for a Lightroom update with lens profile for distortion correction now. Strangely, it seems that my K-3II apply lens corrections with this lens on jpeg...

Article that helped me: Lens Rentals | Blog

My only regret with this lens and all newly released lenses is rounded aperture blades... I need to close to f/16 or f/22 to get good looking sunstars. This is more Photoshop work to combine f/8 and f/22 images for cityscape work, and it's more time on the field.
Forum: Pentax SLR Lens Discussion 03-23-2019, 12:08 PM  
Sigma 18-35 f/1.8 Art Focus Issues Thread
Posted By superdave
Replies: 233
Views: 32,496
New copy was worse than first one, serious decentering, right side was super blurry.... Default focus using the viewfinder result in bokeh everywhere... I returned it, and I will retry in another store...
Forum: Pentax SLR Lens Discussion 03-19-2019, 01:58 AM  
HD PENTAX-DA★11-18mm F2.8ED DC AW
Posted By superdave
Replies: 83
Views: 7,215
Forum: Pentax SLR Lens Discussion 03-13-2019, 05:58 AM  
Sigma 18-35 f/1.8 Art Focus Issues Thread
Posted By superdave
Replies: 233
Views: 32,496
New copy is on the way, I hope it will have sharp edges at 18mm!
Forum: Lens Clubs 03-10-2019, 10:30 AM  
Show us your HD Pentax-DA* 11-18mmf:2.8 DC AW images.
Posted By superdave
Replies: 25
Views: 2,360
Got my new copy and both sides look equally sharp/soft now :)
Left side is a little sharper than my first copy, but right side is a little softer, probably a side effect of the decentring which make the right side sharper than normal on my first copy...
So edges are not as perfect as I thinked in the first place, especially at 11mm and 12mm.
I would say the lens is a little sharper than 12-24mm, but not that much when closed down. It has a little less CA, and contrast is a little better too.
All in all, it perform better than 12-24, and build quality is far superior in all points!
One interesting thing is that 12mm on the 11-18 have a larger field of view than on 12-24.

I also tested sunstars, but I am a little disapointed as you have to close to f/16 or f/22 to really see them (bloody rounded aperture blades...).

Here are a few DNG for those who want to see how the lens perform: WeTransfer
Forum: Pentax News and Rumors 03-08-2019, 03:55 AM  
Just another CP+ report [pics included]
Posted By superdave
Replies: 142
Views: 9,135
Not bad at all, I don't have a K-1 and I didn't remembered that there were such updates.
My K-5 and K-3II didn't had any new features, just compatibility with new hardware, and my K-3II still didn't have the 11-18 optimizations.
Forum: Pentax News and Rumors 03-08-2019, 03:24 AM  
Just another CP+ report [pics included]
Posted By superdave
Replies: 142
Views: 9,135
Wow, good price!

This is too bad that Pentax do not release firmware updates with new features (AF, dynamic PS, etc...), camera bodies would live longer.

Anyone know if the Ricoh interview happened? Usually there is a report very soon after CP+ on PF.
Forum: Pentax SLR Lens Discussion 03-07-2019, 03:24 PM  
Sigma 18-35 f/1.8 Art Focus Issues Thread
Posted By superdave
Replies: 233
Views: 32,496
Yes this is really sad to have to use it in manual... May be the K-3II successor will be a mirrorless so no more focus issue.

One question about the 18-35, do you have sharp edges if you shot a landscape at 18mm when focusing using LiveView?
On my copy, I have no problem between 24 and 35mm, but between 18 and 22mm, edges are not sharp at all (not in focus I think) when using LiveView. And focusing using the viewfinder is total random...
Forum: Pentax SLR Lens Discussion 03-05-2019, 04:23 AM  
DA*11-18mm/F2.8 on PENTAX K1mk2 (FF MODE Vignetting TEST)
Posted By superdave
Replies: 9
Views: 1,133
Most similar lens in regards to AF is probably 20-40 Limited, same technology.
Forum: Lens Clubs 03-04-2019, 05:20 AM  
Show us your HD Pentax-DA* 11-18mmf:2.8 DC AW images.
Posted By superdave
Replies: 25
Views: 2,360
Thanks everyone, I already tried the suggestion of clackers, shooting the same scene with the camera upside-down to be sure that the left edge softness is not because of the scene, and it is not because of the scene as the softness goes to the right side.

I also tried the test of focusing on an object at infinity, using the clamp to lock focus (very nice feature) and shooting the object in each corner. The two left corners are less sharp that the two right corners.

I took many shoots during the weekend and I am always a little disapointed to see the left edge (and also the left ground corner) blurry while the right edge is perfectly fine, so I will return the lens tomorrow for exchange, and cross my fingers to get a perfectly aligned lens next time, I suppose there are good copies.
Forum: Lens Clubs 03-03-2019, 11:08 AM  
Show us your HD Pentax-DA* 11-18mmf:2.8 DC AW images.
Posted By superdave
Replies: 25
Views: 2,360
Hi everyone, just wondering if you have checked if your lens is perfectly centered?

After a close look at my test shots, I noticed that the extreme left of the frame is noticeably softer than the right of the frame, on about 10% of the frame (right edge is very sharp).
It is visible from 11mm to 15mm and I need to close down to f/11 to have the same edge sharpness left/right.
Is your left/right of the frame equally sharp?

I still have two days to exchange the lens, but I would like to know of others copies are perfectly fine.

Thanks!

photo: left side inverted next to right side inverted.
Forum: Pentax News and Rumors 03-02-2019, 09:33 AM  
HD Pentax-DA★ 11-18mm f/2.8 - some local indoors pre-series test shots
Posted By superdave
Replies: 59
Views: 10,904
I think that most sample shots found on review sites (like optyczne, ephotozine, etc...) are not really representative of the image quality of a lens. Most of the time, samples shot are taken handheld and reviewer seems to don't care if the focus is accurate or not. I've seen many samples on optyczne totally blured or out of focus. I don't understand why they put bad samples on their samples page.
Forum: Pentax News and Rumors 03-02-2019, 03:08 AM  
Ricoh booth at CP+
Posted By superdave
Replies: 476
Views: 35,909
FF camera price decrease, but FF lenses price keep increasing. So APS-C is still the best choice for many.
Moreover, Canon RP at 1300€ is a bad information relayed by the rumors, the real retail price is 1499€ (in France), which is the price we found new K-1 mark I now.
Forum: Pentax News and Rumors 03-01-2019, 09:09 AM  
CP+ 2019 - New lens roadmap - DA Standard Zoom added - Fish-Eye Zoom removed
Posted By superdave
Replies: 104
Views: 10,792
Actually it's a good news, it mean that it will be a huge improvement.
Forum: Pentax News and Rumors 02-28-2019, 03:08 AM  
CP+ 2019 - New lens roadmap - DA Standard Zoom added - Fish-Eye Zoom removed
Posted By superdave
Replies: 104
Views: 10,792
Reduced focal range mean higher quality, so a 16-45 f/4 lens WR would be very welcome for landscape photographers if IQ is better than 16-85 and 16-50.
Forum: Pentax SLR Lens Discussion 02-28-2019, 02:16 AM  
Size comparizon between DA* 16-50 and DA* 11-18.
Posted By superdave
Replies: 22
Views: 2,002
I look forward for the review :)

---------- Post added 28-02-19 at 10:20 ----------



I hope so, but the lens on the roadmap is red (DA, not DA*) and the patent is just for a tiny tweak to the optical formula to reduce CA. The 16-50 need a redesign from the ground up to match 11-18. But, I guess a 18-35 is more likely to match optical quality of 11-18 than a 16-50.
Forum: Pentax SLR Lens Discussion 02-28-2019, 12:08 AM  
Size comparizon between DA* 16-50 and DA* 11-18.
Posted By superdave
Replies: 22
Views: 2,002
I got the lens yesterday and my first test pics show outstanding sharpness edge to edge at all focal length. Lens is already very sharp edge to edge at f/2.8, f/8 is the sweet spot. It is better than sigma 18-35mm: equally sharp at f/8, sharper wide open, less CA, no field curvature detected, no focus problem detected so far... (just tested LiveView). It's in another league than 12-24 that I own too.

Now I desire even more a 16-50 or 18-35 mark II with such IQ.
Forum: Lens Clubs 02-27-2019, 03:08 PM  
Show us your HD Pentax-DA* 11-18mmf:2.8 DC AW images.
Posted By superdave
Replies: 25
Views: 2,360
Just a few test pics in poor lighting for now:

Tack-sharp edge to edge @ f/8
11mm f/8
18mm f/8
14mm f/8
11mm f/8

Already very sharp edge to edge @ f/2.8 (no field curvature)
11mm f2.8
14mm f2.8
18mm f2.8
Forum: Pentax News and Rumors 02-27-2019, 01:35 PM  
HD Pentax-DA★ 11-18mm f/2.8 - some local indoors pre-series test shots
Posted By superdave
Replies: 59
Views: 10,904
Few samples of my DA* 11-18mm :

Lens is tack-sharp edge to edge at any focal length @ f/8!

11mm f/8 -> https://c2.staticflickr.com/8/7825/40266170663_b28f3183d2_o.jpg
18mm f/8 -> https://c2.staticflickr.com/8/7900/33355471218_52dc92fd50_o.jpg
14mm f/8 -> https://c2.staticflickr.com/8/7877/33355470738_8fe6194197_o.jpg
11mm f/8 -> https://farm8.staticflickr.com/7886/40266235003_b32b5ccd06_o.jpg

p.s. sorry for the bad lighting, sun was set when I get home, but as you can see, lens resolve tons of details even in shadows... (with no sharpening).

Great job Pentax!

Now, please do a new DA* 16-50mm with similar quality and take my money!

---------- Post added 27-02-19 at 21:48 ----------

I just noticed that the lens is also very very sharp at f/2.8, almost as sharp as at f/8

11mm f2.8 -> https://farm8.staticflickr.com/7815/33355719118_1c1028c34f_o.jpg
14mm f2.8 -> https://farm8.staticflickr.com/7909/32289410087_82f0c9aeda_o.jpg
18mm f2.8 -> https://farm8.staticflickr.com/7922/33355719368_d038219845_o.jpg
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