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10-02-2016, 01:32 AM   #16
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K1 focusses correctly in very low light
K1 with D-FA100M produces much less noise
D-FA 24-70 and 70-200 are fast
K1 AF may not be perfect, but things are getting slightly better

10-02-2016, 09:05 AM   #17
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QuoteOriginally posted by biz-engineer Quote
Thanks for the clarification. I own a K1 and I went through focus issues. Two practical things to consider with the K1:
- Area of PDAF points: K1 points are larger than K3 (AF module was borrowed from the K3, but to cover a larger frame without additional AF points). When focusing on a surface that is smaller than actual size of AF point, random error is introduced by the non overlapping portion of the AF point area and subject.
- AF systematic error require fine tuning (same as other DSLR).
In order to distinguish what is the problem you are having, use a good sized subject, if focus error disappear, then you've got to consider AF point area in your shooting, if focus error does not disappear, then you've got to go through a AF fine adjust.

---------- Post added 02-10-16 at 08:54 ----------


If you are doing portrait shot with 50mm f1.8 on FF ("focus on the eye"), then your camera is positioned at about 5 feet from your subject, in that case K1 is capable of focusing on the eye without error (except if your camera copy is out of spec). If you want to focus on the eye and have shallow DoF with the eye in focus, and you are 30 feet from the subject, in that case, the K1 AF point area is too large to focus on the eye, but anyway DoF is so large (even at f1.8) that whether you focus on the eye or on the head does not matter much.

To be honest, if your K1 is within tolerances, AF fine tuned, you should not have issues within realistic shooting distance (given focal length). Now , if you try to explore the limits of K1 AF capabilities by using uncommon focus conditions, you'll defeat it faster than with some other brands of cameras. I mean, as a photographer, the goal is not to use conditions to make the camera AF fail. The amount of sharp photos with tiny DoF that have already been posted by many K1 owners in various threads of Pentax forum (shot with 77 f1.8, 85 f1.4, 300 f2.8, 450 f5.6) bring some evidence that K1 AF works well including with f1.4 lenses.
I have sharp portraits wide open too, what I'm saying is that acquiring focus sometimes is an issue, with eye sharpness varying in the same set, with same parameters. I thought it's just the cheapo lens with the screw drive motor, but maybe it is the system, in that case I'm probably never going to achieve the level of fast and accurate focus that I had with my mft body which I didn't expect (I actually expected the opposite).

I'm not denying other spec improvements I got with k-1, images look great, noise level is incredibly low, dynamic range yada yada, all true. But since everyone in dslr world keeps crapping on mft bodies for their inferior focusing capabilities, especially tracking the subject, I thought a flagship dslr such as k-1 would show some improvements in that area too, which I guess it doesn't. I really should just rent a D fa lens and see for myself, people's reports even in this thread vary quite a bit.

Last edited by awscreo; 10-02-2016 at 10:33 AM.
10-02-2016, 10:09 AM   #18
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I find every camera takes a bit of getting used to.... lenses also make a difference. I went out yesterday with an FA 50 macro, and didn't get much. II usually use a Sigma 70 macro or Tamron 90 macro, either would have been much better. I'm just beginning to process what went wrong.
10-02-2016, 11:57 AM   #19
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QuoteOriginally posted by awscreo Quote
what I'm saying is that acquiring focus sometimes is an issue, with eye sharpness varying in the same set, with same parameters.
Short version of the above; If the af point size is relatively small compared to the size of area I want to focus on, the AF of my K1 is very repeatable (using DFA lenses). If I'm trying to AF on small area, then, Af is less consistent. Take it or leave it.

10-02-2016, 01:44 PM   #20
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Seen a post suggesting AF-C plus back AF button might improve focusing accuracy. Will test and see
10-02-2016, 02:51 PM   #21
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QuoteOriginally posted by awscreo Quote
Seen a post suggesting AF-C plus back AF button might improve focusing accuracy. Will test and see
Should make no difference unless the subject is moving and even then accuracy is the same for the focus point being used. There is no hack or magic.


Steve
10-02-2016, 03:58 PM   #22
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QuoteOriginally posted by KiloHotelphoto Quote
I will give that a try, got about six to seven weeks until the eagles really start to show up in the hundreds. Hopefully I will be able to get some shots to share.

I've seen a couple of your other shots, really looking forward to more, KHP!
10-02-2016, 05:08 PM   #23
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QuoteOriginally posted by stevebrot Quote
Should make no difference unless the subject is moving and even then accuracy is the same for the focus point being used. There is no hack or magic.


Steve
Not looking for magic, looking for ways to improve focusing and reduce the possibility of having out of focus shots due to mine or subject movement.

10-04-2016, 03:13 PM   #24
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QuoteOriginally posted by awscreo Quote
Not looking for magic, looking for ways to improve focusing and reduce the possibility of having out of focus shots due to mine or subject movement.
Looking for the same thing, will be following this closely!
10-04-2016, 04:30 PM   #25
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QuoteOriginally posted by jls74d00 Quote
Looking for the same thing, will be following this closely!
I kind of like this backbutton AF-C thing. The few opportunities I tried it with, due to it always re-focusing on a subject I could bang out like 5-6 images, and 4 at least would be in focus. So you'd at least get few shots you can work with.
If you're interested - here's the technique I'm trying out: https://www.pentaxforums.com/forums/38-photographic-technique/236970-perfect-...everytime.html
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