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Forum: Pentax DSLR Discussion 05-21-2017, 02:24 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
@Normhead With back-button AF you can use AF-C 100% of the time.
Forum: Pentax DSLR Discussion 04-08-2017, 08:39 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I choose these lenses because the Pentax is known for its speedy autofocus. Infinity to MFD is faster than the Nikon (maybe twice as fast), and so is focusing in good light. When the light levels drop, however, things are different. I also noticed this before when I tried to find out if and why my 60-250 focused slower than my 55-300. I tested them side by side at home. The way I tested them was by recording focusing noises using Audacity. Racking through the range was actually slightly faster on the 60-250. But what really surprised me was that both lenses focused significantly slower in low light, with the delay mainly being before the lens actually moved. So before the main run, which gets the focus into the ballpark, and before subsequent micro-adjustments. Seeing as I can reproduce those results with the 16-50 and the 35/2.4, I think there's a pattern here. And since it happens before the motor is activated and seems consistent with whatever kind of motor is used, I think it's the body and not the lenses.

I do think there is a quick fix however: activate the AF assist light sooner.

This is also why I made the video specifically about AF in low light. Although the fact that the 16-50 sometimes failed to lock focus might have had to do with the SDM motor not having enough torque, causing it to jump around the focus point until giving up.
Forum: Pentax DSLR Discussion 04-07-2017, 09:46 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I just did a quick comparison of autofocus on the Pentax 35/2.4 and the Nikon 35/1.8. In good light, the Pentax is faster most of the time because the lens itself just moves faster (when racking the lenses from infinity to MFD the difference is quite obvious). As for accuracy, I focused on my speaker (the one you see in the video), with the ( ) symbol in the Pentax's viewfinder inside the woofer's circumference and using the center focusing point. Still I got some misses where it actually focused on the wallpaper behind the speaker. The AF points in the Pentax are larger than in the Nikon, yet the AF viewfinder indicators are smaller. Depending on the circumstances you might have to work around that more than you have to do with the Nikon. I'm probably not saying anything you don't know though. Also this may not be what you interpret as accuracy. But it is something I feel is relevant to that topic.

I am saying this partially in response to the request for more rigorous testing and testing under different circumstances (that would favour Pentax more). Maybe I'll even make a video about it. On the other hand, the more I do things like that, the more I feel like a camera operator instead of a photographer. There is truth to that, no doubt. And for me personally, that is much more interesting to make a video about or talk about. What I actually wanted with my photography was also a way of letting go of my inner nerd a bit. There are times when I succeed at that, and other times when I still fail.
Forum: Pentax DSLR Discussion 04-06-2017, 07:25 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
All I have for myself is my own experiences. All the tests in the world won't change those.

You like the 18-135. Yet Photozone has objectively tested it and thinks it's terrible. But you don't lose any credibility by liking the 18-135 in my book.

And it's the D7100, not the P7100.
Forum: Pentax DSLR Discussion 04-03-2017, 04:19 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Yeah but she's not really moving. ;)

All kidding aside, nice shots!

And you are right. We can talk all day long, but instead of talking we could shoot. Work with it, play with it, try out stuff. And then if the AF works for you, that's all that matters. And if it doesn't, you know that too.
Forum: Pentax DSLR Discussion 04-02-2017, 05:11 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I've actually been playing with my two bodies (hmm that almost sounds wrong ;)) and I have been getting better results with the line-type sensors on the Nikon than with the line-type sensors on the Pentax (in terms of accuracy). Which is a good thing as the Nikon only has 15 cross-type sensors. I've also been contemplating things a bit, and I think that right now, the gap between Pentax and Nikon AF must be smaller than it was years ago (except maybe for the AF in the D500 which I don't own). The D7100 basically has an upgraded AF from the D300S, which was released in 2009. Pentax, meanwhile, has been pushing a lot of small improvements and tweaks going from SAFOX 8 to SAFOX 11.

No comment on AF-C though.
Forum: Pentax DSLR Discussion 03-31-2017, 07:00 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I will take this one point and reply to it. I have said this before, but I did test with other lenses as well (most notably the Pentax 35/2.4 and Nikon 35/1.8) and had similar results. I wrote this down several times, yet you keep mentioning how I made Pentax look bad by using the 16-50. I also wrote down that the Pentax DA* 16-50mm f/2.8 is actually about as fast as the Nikon AF-S 17-55mm f/2.8 when going through the focus range (from infinity to MFD and back again).

It is these kinds of comments, repeated after I confronted them head-on, that make me think you won't accept my answer anyway. Even if I were to post another video concerning focus accuracy, I think you'd just find another thing to nitpick on. So why should I bother?

About AF accuracy: no I did not test that. From my own experience, I have more confidence in the Nikon. Maybe it's not another matter, but I haven't tested it, so if I did, it could go either way.

---------- Post added 04-01-2017 at 04:17 AM ----------



Ok, you didn't say exactly that. What you did say is this:



I didn't create a review, as you suggested. Not of the K-3 and not of the 16-50. But you seem to assume I did, and you concluded that my review was unfair to the K-3 and 16-50 (which I loosely translated to "you accusing me of saying they are rubbish"). So first you assumed something, and then you criticized me based on that assumption. But the assumption itself was invalid.

Do you see why I have a problem with these kinds of replies?
Forum: Pentax DSLR Discussion 03-31-2017, 06:35 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Forgive me, but... you are posting shots taken with MF in a topic that concerns AF. I mean, I thought you posted those pics to show that you can get good results from AF with birds flying toward the camera. Which may still be true, but that's another matter.

Before, you kind of accused me of saying the 16-50 is a rubbish lens. I never said that either. I mean, is it so strange that I sometimes react the way I do with comments like these? Sorry, but if it is, then I just don't get it here.
Forum: Pentax DSLR Discussion 03-31-2017, 06:21 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
No I don't. And I hope not. What everyone is doing here is each member's individual business.
Forum: Pentax DSLR Discussion 03-31-2017, 05:05 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I do want to say this: I don't care if someone says a certain system is inferior based on his or her shooting style. The only thing that matters to me is how does the camera contribute to the end-result I'm after? It is a tool, just like a lens or Lightroom or a memory card or something else.
Forum: Pentax DSLR Discussion 03-31-2017, 04:07 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Thank you for your feedback.



Err.. I was responding to photoptimist writing that overlays were something of a novelty. We weren't even discussing Pentax cameras, but mirrorless and DSLRs in general and where technology is headed. But you're right; I made a comment about Pentax which could be considered negative. I will rewrite my post (even though that was not my angle).



If you are responding to me saying that I think IBIS is more at home on mirrorless cameras, we weren't talking about Pentax or Sony or Canon or Nikon, we were talking about camera technology in general.

As for PSR, you're right, Nikon doesn't have it. And some other features as well.



I also posted some shots I took with my K-5 and even my K-7 with the 55-300 which I think are pretty much spot on in terms of AF.



I am open to the possibility that I'm doing something wrong. I guess I'll find out either way.



Usually I'm having problems locking on to birds that come flying at the camera. Can I ask you some questions about these photos?

edit: Never mind. You're still editing your post and I'm not going to go there. Like I said before: you and I differ on some opinions. That became very clear when we were discussing my video.
Forum: Pentax DSLR Discussion 03-31-2017, 08:34 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
To be honest, Nikon had LCD viewfinder overlays since at least 2008 (D300). AF points, grid, battery status, etc. Even the D200 had overlays. You may not want to consider it a recent innovation.
Forum: Pentax DSLR Discussion 03-31-2017, 12:36 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
The KP does not have on-sensor PDAF: Pentax KP Review: First Shots
Forum: Pentax DSLR Discussion 03-30-2017, 11:31 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Ok, you seem to know more about this stuff than I do. :) Thanks for the information.
Forum: Pentax DSLR Discussion 03-30-2017, 06:57 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
But if you look at the D500, it also has AF sensors spread throughout the viewfinder area. And I think the applicability of lenses slower than f/5.6 is small anyway.

However, on-sensor AF does make it easier for a manufacturer to create a reliable phase-detect AF system. And with mirrorless, there are less moving parts in the camera which should make it easier to develop and more reliable. I think IBIS is also more "at home" in a mirrorless camera, as it stabilizes the viewfinder, AF and light metering sensor as well.

From a purely technological point of view, I think DSLR versus mirrorless is like CD player versus media player. And err... I don't have a CD player anymore. Even though I'm Dutch and it was at least partially a Dutch invention. ;)

But the upside is that CD players are cheap. The same goes for DSLRs and their lenses. And for some applications, mirrorless is just not as good as DSLR (yet).
Forum: Pentax DSLR Discussion 03-29-2017, 08:13 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
In all fairness, my D7100's AF isn't perfect either. I recently found out that the AF points on the left side backfocus slightly. It can apparently be fixed though.
Forum: Pentax DSLR Discussion 03-28-2017, 03:15 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Anyway, here's one of those pics I took in Africa:



It's a slight crop. This was no problem for the K-5 and DA 55-300 (screw-drive).

I do feel that, somehow, the success rate with birds flying away from the camera is generally higher than with birds flying towards the camera (which may generally yield more interesting photos).
Forum: Pentax DSLR Discussion 03-27-2017, 02:43 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
There are so many variables involved though. I once shot flying pelicans at a lake in Africa. The K-5 and screwdrive 55-300 were up to the task, from a perpendicular view to them flying away from me at an angle relative to the camera. But the background was mainly the sky, so the AF had little choice but to lock on to the birds. I believe I used auto-AF selection and it worked because of that. Also, it was a clear and sunny day, so the AF was quite responsive (e.g. very different from my video).

But I do subscribe to what is also mentioned in the review; in terms of feedback provided by the tracking AF, Nikon is so much nicer to use. The active AF point is always displayed so you know what the camera is tracking. With my K-3, I will find out eventually if tracking is off. But I'd rather know sooner than later. Then at least I know when it's any use to press the shutter, which leads to less "spray and pray" action, less images to go through afterwards and it mitigates the disadvantage of the smaller buffer.
Forum: Pentax DSLR Discussion 03-27-2017, 11:27 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
They say AF-S performance is quick and direct. So maybe there are substantial improvements relative to the K-3 after all.
Forum: Pentax DSLR Discussion 03-27-2017, 03:13 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
True, this is already more challenging:



Still perpendicular to the camera, but closer up already (although this is a crop as well). I shot this with the K-7 (so no tracking at all) and the screw-driven 55-300.

I will say this though: there weren't many shots in proper focus like this one.
Forum: Pentax DSLR Discussion 03-25-2017, 06:56 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
One last thing I want to say about my video: perhaps I did go a little overboard by implying the Nikon was in perfect focus. I mean, it wasn't bad (the metal ridge underneath the speaker is sharp) but maybe it wasn't perfect either. But I already explained that the lens isn't calibrated and that it did look much better on the screen than it does in the video. But yeah, maybe I shouldn't have said it that way in the video.
Forum: Pentax DSLR Discussion 03-25-2017, 05:30 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Thank you for making me smile once more. ;)
Forum: Pentax DSLR Discussion 03-25-2017, 04:26 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Concorde - so maybe you ARE just as rich as Trump? ;)

Anyway, I was in a similar situation (not in terms of wealth, but photographically) when I tried shooting my little niece on a swing several years ago (actually right after that MotoGP race) using the K-3 and DA* 60-250. It also could not keep up at all. But to be honest, the images also didn't look that great. So I experimented, put the 16-50 on and prefocused at maybe 1 meter. Then I put the camera near the ground, pointing upwards, and shot her at 16mm. It turned out to be a great success. I got her, part of the swing, the surroundings and a nice sky behind her, with a lot of depth because of the wide angle. The only thing was that she was kind of dark, so I probably should have used a flash to brighten her up a bit. But other than that, it was great. Just looked up the image again, and she turns out not to be so dark - so actually, a pretty nice photo! So actually, in that case, the lack of focus speed wasn't so much of a problem.
Forum: Pentax DSLR Discussion 03-24-2017, 12:01 PM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
I've been smiling for a while now. I wasn't smiling when normhead and I were kind of negative towards each other, but that was ages ago. ;) And I'm also smiling because of the way I handled that. :)

I'm not complaining, I'm just saying I have more confidence in Nikon's AF. Like I've said before, there's nothing wrong with that I think. I might be complaining if I hadn't bought the Nikon gear, because then I'd be frustrating myself. Also, if you have a DFA 28-105, you probably also have a K-1. So you've probably already spent way more money on your gear than I have. And you probably upgraded from an APS-C Pentax camera. I could therefore say the same to you: why upgrade to fullframe when you can be happy like the people in Laos?

By the way, Cambodia is in far worse shape than Laos. 1/4 of its population was murdered by Pol Pot in the 70s, and it was the intelligent 1/4. Teachers, thinkers, etc. They are still trying to recover from that. I've seen a man there, called Beat Richner, who has build children's hospitals. He could have probably chosen a career in the west and make a lot of money. But he choose that life. Makes you think (at least, it makes me think).

But you're right, our "problems" aren't really problems. We're just good at inventing problems because all our immediate needs are covered. Even Donald Trump, who has way more money than anyone of us, has "problems" (though maybe we shouldn't go there ;)). But then I have to ask: why was this topic even created?

The answer also is: whoever you are, whatever you do, however much money you have, try to be happy and at peace with yourself and those around you. If you can't change something, learn to see it in a positive way. If you can, you can change it. Laos is a Buddhist country as well.

I'm also not going to make a problem about what you wrote that there's always an error. That's evident. Still I have more confidence in Nikon's AF. I believe the error will be smaller. My initial testing seems to confirm that, though I haven't yet taken actual shallow DOF photos of moving subjects with it yet.
Forum: Pentax DSLR Discussion 03-24-2017, 10:41 AM  
Pentax, autofocus and the future
Posted By starbase218
Replies: 287
Views: 30,335
Please re-read my earlier posts. I did not just test it with the 16-50. I also tested the K-3 and the DA 35/2.4 (which I believe is one of the fastest focusing Pentax lenses) against the D7100 and the 35/1.8. I saw similar differences. The Pentax actually outperforms the Nikon when going through the entire focus range, but the system as a whole is more hesitant when trying to lock on, which makes it slower.

Maybe DC motors are an improvement, but I don't see how. A motor is a device that turns electrical energy into mechanical energy, nothing more.

I guess I'm talking about the other half of the performance.
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