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Forum: Pentax SLR Lens Discussion
12-24-2017, 01:29 AM
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Forum: Pentax SLR Lens Discussion
12-24-2017, 12:54 AM
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Let me give you the words on sharpness from the link you provided - if you want to dispute their results, best take it up with the authors:
Conclusion
The results of the Edmund Resolution Power Chart were very interesting. Initially, the Sigma DG 12-24 f/4.5-5.6 slightly out-performed the Pentax DA 12-24mm f/4. However, once the Pentax lens was either stopped down beyond F4 or zoomed beyond 12mm it performed marginally better than the Sigma. The Tamron came in third.
The field sharpness test told a different story. The Pentax lens consistently performed better than the Sigma throughout the zoom range and regardless of f-stop. The Tamron again came in third place.
You can see my pictures above, it's not decentred. I like it.
My Pentax is sharper and faster, my Sigma is wider, this tallies with the official review by this forum you've already quoted, case closed despite your protests, right? ;)
Perhaps, James, you have pictures of your own to show that both Pentax Forums and I have this the wrong way round ... that by coincidence, we both received dud copies. Side by side on film of the same subject with your Sigma and Tokina, you know, controlling variables, all that boring stuff required of legitimate evidence .... :)
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Forum: Pentax SLR Lens Discussion
12-23-2017, 01:36 AM
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Unlike you, I have both a K-1 and the Sigma 12-24.
I agree with that quoted article's finding that in real life sharpness shots, "The Pentax [DA12-24] lens consistently performed better than the Sigma throughout the zoom range and regardless of f-stop."
However, the Sigma on FF is 12-24, not 17-24, so that's why I bought it this year, also refurbished, from Sigma in the States.
A couple of shots with it. Plenty of flare and chromatic aberration in the backlit left part of the first picture, but that's to be expected with these bulbous front elements. The Pentax's is less prominent and can in fact take a screw-in filter.
If you don't understand, just ask me or anyone else, we'll help you, but please stop bluffing your experience or knowledge!
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Forum: Pentax SLR Lens Discussion
12-21-2017, 04:21 PM
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I have shot the DA35 and DA50 just fine on my Sony A7 as well, Scooter. :)
Any lens that vignettes badly on APS-C will vignette even worse on FF.
You can see that on the DxO results for the Zeiss first with the D500, then the D810.
I'd like to see your proof of anything different. :)
Yet again, you're mistaken.
I'm not trying to win you over, Jim, I've already been thanked by PM for calling you out in this thread. :)
Again, a consistent theme for you, what is your proof?
Let us see your pictures backing your claim.
Here are mine on the K-1. Many people can't afford the DFA 15-30, the DA12-24 is one of their options, and they may already own one.
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Forum: Pentax SLR Lens Discussion
12-20-2017, 08:18 PM
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(Laughs)
Did you think I was comparing those FF lenses on FF sensors?
It speaks a great deal about how evidence presented won't shift an attitude, when you don't even own a K-1.
So, let me explain.
Photozone measured the DA50 as having a 0.7 eV loss on APS-C ... Pentax SMC DA 50mm f/1.8 - Review / Test - Analysis
The DFA 50mm f2.8 Macro has a 0.7eV loss on APS-C. Pentax D FA 50mm f/2.8 macro - Review / Test Report - Analysis
The FA50 f1.4 has a 0.7eV loss on APS-C. Pentax SMC-FA 50mm f/1.4 - Review / Lab Test Report - Analysis & Verdict
I said the mighty Zeiss was tested on the D500 - not the D5. It's APS-C .. and guess what?
-0.8eV. Carl Zeiss Milvus 1.4/50 ZF.2 Nikon mounted on Nikon D500 : Tests and Reviews
If you're hoping for a miracle, Jim forget it. None of these lenses will get better on FF - the Zeiss sinks to -1.6eV, according to DxO.
Are you actually objecting to the particular pictures of a fun day in a garden, James?
You don't seem to pay much attention to what others do, so here's where you can start your education, from your Pentax Forums colleagues ... :)
DA35 f2.4 - the Plastic Fantastic club - PentaxForums.com
Fantastic Fifty! The DA 50mm F/1.8 - PentaxForums.com
While you're criticizing these wonderful cheap lenses - glass to be proud of in the Pentax lineup - people are enjoying and using them. Even though I own the Sigma 35 Art and DA*55 (top two lenses in DxO's rating here ... guess what's at three and six? https://www.dxomark.com/best-lenses-for-the-24-mpix-pentax-k-3-recommended-primes-and-zooms/) , I reckon, more power to them!
BTW, the DA12-24 is regarded in that DxO list as *the* ultrawide zoom to have, and is in the Pentax Forum's official recommended gear guide. So, your opinion is ... just your opinion, I'm afraid. :D
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Forum: Pentax SLR Lens Discussion
12-20-2017, 05:50 PM
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As usual, James, you assert things instead of use the real data at places like Photozone, or the hundreds of photos your fellow members have actually taken on FF.
According to Photozone, the DA50 and FA50 actually vignette the same as the film era FA50 f1.4 and the newer DFA 50mm f2.8 Macro, and are superior to the FA31 Limited.
And according to DxO, better than the mighty Zeiss 55mm Otus f1.4 on a Nikon D500. Are you going to argue the $4000 Zeiss isn't really a full frame lens?
You can check out Rice High's findings here:
RiceHigh's Pentax Blog: Compatibility of DA Lenses on Full Frame
Our ratings, findings and real life shots going back nine years here:
DA lenses on Full Frame: Test Shots thread - PentaxForums.com
I spent a day with the K-1 shooting nothing but the plastic fantastics in FF mode to get shots that according to you, are apparently impossible ...
Autumn in the Dandenongs - PentaxForums.com
If you want to encourage consumerism and convince Pentaxians their much loved current lenses are no good, and they've got to spend more money, I can't condone that, I'm afraid.
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Forum: Pentax SLR Lens Discussion
12-08-2017, 04:08 PM
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Correct. That's how lucky we are.
We should appreciate the efforts of our fellow forum members for all their assistance, and become financial supporters to look after the place that makes it all possible. :)
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Forum: Pentax SLR Lens Discussion
12-08-2017, 01:08 PM
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We have our own thread here, Alex, which has an extensive list of lenses and real reports.
As usual, this place provides accurate information versus 'what's out there'. I wouldn't trust B&H and Tony Northrup or whoever to get anything right.
As a generalization, any normal or tele DA prime works, but no DA zoom.
Even in the case of the zooms, they often work fine at the long end (my DA12-24 f4 is great from 17mm on, which becomes attractive to anyone who finds the DFA15-30 too expensive or big) or in the case of the DA*60-250, removing an inner baffle makes a real difference to vignetting.
Going full frame can be less expensive than APS-C owners think, especially with Pentax.
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Forum: Pentax SLR Lens Discussion
12-08-2017, 04:55 AM
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Irritatingly, the Novoflex is clickless. :)
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Forum: Pentax SLR Lens Discussion
12-08-2017, 04:11 AM
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It's Full Frame, Alex, this has been known for years and reported on this forum.
There is a thread where I posted pics of a day in a park where I used only the K-1 and the DA50 and DA35.
Before the K-1 was even released, I had used the DA50 on my Sony A7.
These plastic fantastics are a great pair of sharp, cheap primes Pentax can be proud of.
They of course have 35mm heritage in the M50 f1.7 and FA35 f2. :)
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Forum: Pentax SLR Lens Discussion
12-07-2017, 10:41 PM
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Sure, reducing the size of a lens is a design compromise.
Take away glass and it can't cover the frame completely, it distorts or there are aberrations robbing sharpness.
Then you have to compensate with other features of your design.
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