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08-07-2016, 10:38 PM   #46
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QuoteOriginally posted by dr_romix Quote
None of them are calibrated.

You need to go through this with all lens purchases, Dr_Romix ... I don't know why you haven't already.


They may need zero adjustment ... but that's not the point.


No one here is interested in 'prove I'm right' pics taken with uncalibrated lenses.

08-08-2016, 04:06 AM   #47
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QuoteOriginally posted by HoustonBob Quote
What I see is a full frame camera with a 24-70 and some aps-c cameras with the equivalent of 36-105 lenses on them. The pictures appear to have been taken from the same location. The longer equivalent focal length on the the aps-c cameras causes the image of the face to look larger and thus the eye is able to see more detail in the aps-c shots. Please use the same equivalent focal lengths if you want to produce the same size images of faces from the same distance. In other words your test is just accidentally biased.
Thanks for your comment, but I kinda of disagree with you. Eventhough these photos aren't taken exactly at the same focal length, - tried to be as close as possible - it doesn't justify to me why K-1 isn't sharp compared to Nikon or Sony. Pic taken with K3 has almost identical focal length as the Nikon and Sony. Given full frame sensor and K-1, few focal length difference shouldn't give me a blurry pic. As a matter of a fact, going over more than 500 pics at different FL and aperture, I took during my recent trip, sony was lot more clear and sharper than K1. Also comparing my pics with K3-Tamron paired to my K7 Tamron paired, I see K7 was sharper and Tamron has some front focusing on my K3.

---------- Post added 08-08-16 at 06:10 AM ----------

QuoteOriginally posted by clackers Quote
You need to go through this with all lens purchases, Dr_Romix ... I don't know why you haven't already.

I bought my Tamron when I purchased my K7, and didn't have problem on either K7 or K5. With K3, I didn't use it that much till now.
As far as the other ones, I just bought the camera and comparing the result that's why I have posted to get feedback as whether the lens-camera is the issue or the technique.


They may need zero adjustment ... but that's not the point.


No one here is interested in 'prove I'm right' pics taken with uncalibrated lenses.
As I said above, it's not about " I'm right ", it's about whether the camera-lens are the issues or the techniques given my limited return allowance time frame I need to make a decision on these camera-lenses
08-08-2016, 04:27 AM   #48
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QuoteOriginally posted by dr_romix Quote
As I said above, it's not about " I'm right ", it's about whether the camera-lens are the issues or the techniques given my limited return allowance time frame I need to make a decision on these camera-lenses
You should already have tested for:

1. Front/back focus with micro adjustment.

2. Decentreing with flat targets

Each day you don't do this is a day you lose of your return period.



08-08-2016, 05:15 AM   #49
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QuoteOriginally posted by dr_romix Quote
So, I purchased K1 and Sony a6300 for different needs, but when I take pic of my niece and nephew ( still photo ), I see Sony has better focusing system and they face especially their eyes look so much sharper than K1 . I even adjusted AF to 9 points on K1 and focus on their face, but still side by side Sony is sharper. If the kids moves a little bit, then forget it, K1 failed all the time. Here is my gear:

Pentax K1 with Tamron 28-75 f/2.8 initially I shot at 2.8, but then switched to f4 and kept the same ISO settings and AF.C to match Sony
Sony a6300 with Zeiss 24-70 f/4

any help is greatly appreciated .
Unless you use the same lens (not just the the same model of lens, but the exact same specimen.) on both cameras any statement about which camera is sharper is pure guesswork.
The results of any such comparison that include more than one variable are meaningless.

08-08-2016, 06:20 AM - 1 Like   #50
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Thanks for the test....

I always look at results of tests and try and understand what I'm seeing, so do most other people.

SO while this is a great test for you, it tells you about the gear you own. If you aren't going to calibrate your lenses, it is even more important.

But lets be clear

In tests taken with the same lens the lens taken closest to the subject will appear sharpest and show the most detail.

Evaluation of bokeh can only happen with cameras and subjects the exact same distance from the subject and background.

If you don't want to calibrate a lens, don't buy the lens. an uncalibrated lens can be as bad as a defective lens.

While you satisfied yourself that for the gear you own, you've can draw a few conclusions, I would guard against projecting those conclusions across wide ranges of gear, like saying that if someone else shot the same test with the same brands and models with different cameras they'd get the same results.

My suspicion is, if you didn't have so many cameras, by now you would have learned to take the necessary steps to take good images with your K-1. Yet if instead of a K-1 and a Sony you'd bought 2 K-1s, you might just as easily be telling us one K-1 was better than the other K-1.

SO my advice would be, learn how to configure your K-1 to get the images you want. I've seen razor sharp K-1 images, and several sites have suggested that with pixel shift enabled a K-1 will surpass any other 36x24 sensor camera. I don't know how you can claim to have even evaluated a camera you haven't optimized.

That would be supported by another observation from elsewhere in the forum
QuoteQuote:
I never noticed a focus problem with my canon, nor my 1st K-1 body other than my sigma 24-70, which I chalked up to a poor rendition of the lens.

However with my second K-1 body, I was noticing none of my lenses were focusing right, so I bought lens align to help me fine tune things. With the alignment my shots are much better.
But, given the fact that you have access to all these bodies. If you get better images with the Sony, use it. It's the best of your cameras in your personal situation. Put the others back on the shelf or sell them. Go with what works for you. Or as long as you can afford it, just keep buying bodies until you get one that works perfectly right off the shelf.

Some times the best camera for a shooter is the one that's easiest to use.

As for your K-1, there are lots of folks, myself included who would buy your "bad" camera at a discount and make it sing. I've seen enough clear razor sharp K-1 images on the net, like Pinholecam's image of the temple where if you pixel peep, you can read the license plates of the tiny little cars in the parking lot. We know what the camera can do, people are wondering why you aren't doing it.

But what parts of what you've posted is relevant to me? All those cameras take nice pictures. I can work with any one of them. So why would I use the most expensive set up? You've repeated which ones you think are sharpest, but I certainly can't tell from what you've posted. Clearly at web size it makes little difference. I suppose you could argue that there will be some form of output ( like maybe a 20x30 print, but i would still like to see visual confirmation of that before I believed it ) where it does make a difference, but no one has any idea exactly where that would click in.

Last edited by normhead; 08-08-2016 at 06:46 AM.
08-08-2016, 07:47 AM   #51
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QuoteOriginally posted by dr_romix Quote
Thanks for your comment, but I kinda of disagree with you. Eventhough these photos aren't taken exactly at the same focal length, - tried to be as close as possible - it doesn't justify to me why K-1 isn't sharp compared to Nikon or Sony. Pic taken with K3 has almost identical focal length as the Nikon and Sony. Given full frame sensor and K-1, few focal length difference shouldn't give me a blurry pic. As a matter of a fact, going over more than 500 pics at different FL and aperture, I took during my recent trip, sony was lot more clear and sharper than K1. Also comparing my pics with K3-Tamron paired to my K7 Tamron paired, I see K7 was sharper and Tamron has some front focusing on my K3.

---------- Post added 08-08-16 at 06:10 AM ----------


As I said above, it's not about " I'm right ", it's about whether the camera-lens are the issues or the techniques given my limited return allowance time frame I need to make a decision on these camera-lenses
At least try to focus with the K-1 using live view. If you don't get a sharp image with that, then you can say that is probably a lens issue. If you get a sharp image with live view, but not with focus through the viewfinder, then focus adjustment will take care of it.

I don't own the Tamron 28-75. From what I have read, it is an OK lens on full frame. Suffers from weak borders, but otherwise should be fine, but I suppose you can't rule out that the Tamron isn't playing nicely with the camera -- this is something I have heard about with the Tamron 17-50.
08-08-2016, 08:51 AM   #52
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dr-romix: one more thought to share in addition to the many other good ones already posted. All of your shots are portraits so maybe the best determinant of sharpness for you is with some good medium length prime lenses. I'm almost certain those lenses will give better ultimate results if you want to really make close judgments between the cameras.
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