Why do Pentax lag with autofocus?


Frogfish

Link Posted 28/01/2013 - 07:56
Smeggypants wrote:

It can only be down to neglect of AF performance as a priority. It's one area where Pentax need to raise their game considerably to get more inroads into the pro-market where shots can't be missed and the job needs to get done. Sports, papparazi, gigs and so on.

As a hobbyist people shooter I would also like a much more response and accurate AF.

I'm not sure it's neglect so much as a different priority Smeggy.

Pentax don't have long or fast sports/wildlife/bird lenses so, as the famous (or infamous) tests carried out by that French magazine showed, they seem to prioritise reliable focusing over speed of focusing.

In that test Pentax came out ahead of all other manufacturers in % of shots actually in focus (it was a high % but I can't remember or find that link - maybe someone else can), it was in the 90%+ I believe. Maybe this is the micro-focusing we often hear from Pentax lenses (I found the Sigma's HSM faster and without the micro-focusing) which also detracts from the locked-on focus speed.
http://frogfish.smugmug.com/ Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0

Smeggypants

Link Posted 28/01/2013 - 09:54
Frogfish wrote:
Smeggypants wrote:

It can only be down to neglect of AF performance as a priority. It's one area where Pentax need to raise their game considerably to get more inroads into the pro-market where shots can't be missed and the job needs to get done. Sports, papparazi, gigs and so on.

As a hobbyist people shooter I would also like a much more response and accurate AF.

I'm not sure it's neglect so much as a different priority Smeggy.

Pentax don't have long or fast sports/wildlife/bird lenses so, as the famous (or infamous) tests carried out by that French magazine showed, they seem to prioritise reliable focusing over speed of focusing.

In that test Pentax came out ahead of all other manufacturers in % of shots actually in focus (it was a high % but I can't remember or find that link - maybe someone else can), it was in the 90%+ I believe. Maybe this is the micro-focusing we often hear from Pentax lenses (I found the Sigma's HSM faster and without the micro-focusing) which also detracts from the locked-on focus speed.

Well I would have thought 'sales' was the maximum priority of any company.

Quote:
they seem to prioritise reliable focusing over speed of focusing.

Interesting comparison. Surely the subject matter determines what's considered 'reliable' in terms of AF

i.e for dynamic subjects ( anything where the moment is fleeting - sports, people, wildlife, etc ) then I would place speed of focussing the biggest factor in reliability. There's no advantage in having slow AF that's always accurate when you get home and have an SD card full of pics that that show the scene after that magical moment?

After all if you're into photography of landscapes or other static subjects then even manual focus is fine.

Don't get me wrong, I love a finely crafted landscape shot, but one of the things that most excites me about photography is going out and searching out fleeting moments in the world and trying to capture them.

Two things that that a big help to this are great ISO performance and great AF performance.

I still maintain Pentax need to raise their game in AF speed.
[i]Bodies: 1x K-5IIs, 2x K-5, Sony TX-5, Nokia 808
Lenses: Pentax DA 10-17mm ED(IF) Fish Eye, Pentax DA 14mm f/2.8, Sigma 17-70mm f/2.8, Pentax-A 28mm f/2.8, Sigma 30mm F1.4 EX DC, Pentax-A 50mm f/1.2, Pentax-A 50mm f/1.4, Pentax-FA 50mm f/1.4, Pentax-A 50mm f/1.7, Pentax DA* 50-135mm f/2.8, Sigma 135-400mm APO DG, and more ..
Flash: AF-540FGZ, Vivitar 283

dcweather

Link Posted 28/01/2013 - 11:44
Frogfish wrote:
dcweather wrote:

Unfortunately I already do all of the above!
Dave

Ouch ! Nothing else that I can suggest then other than the obvious.

No, Kevin, I was very grateful for your post because I greatly admire your photographs and it told me I was on the right lines with my settings which is what I asked. Thank you,
Dave

dcweather

Link Posted 28/01/2013 - 11:49
Smeggypants wrote:
Frogfish wrote:
Quote:

It can only be down to neglect of AF performance as a priority. It's one area where Pentax need to raise their game considerably to get more inroads into the pro-market where shots can't be missed and the job needs to get done. Sports, papparazi, gigs and so on.

As a hobbyist people shooter I would also like a much more response and accurate AF.

I'm not sure it's neglect so much as a different priority Smeggy.

Pentax don't have long or fast sports/wildlife/bird lenses so, as the famous (or infamous) tests carried out by that French magazine showed, they seem to prioritise reliable focusing over speed of focusing.

In that test Pentax came out ahead of all other manufacturers in % of shots actually in focus (it was a high % but I can't remember or find that link - maybe someone else can), it was in the 90%+ I believe. Maybe this is the micro-focusing we often hear from Pentax lenses (I found the Sigma's HSM faster and without the micro-focusing) which also detracts from the locked-on focus speed.

Well I would have thought 'sales' was the maximum priority of any company.

Quote:
they seem to prioritise reliable focusing over speed of focusing.

Interesting comparison. Surely the subject matter determines what's considered 'reliable' in terms of AF

i.e for dynamic subjects ( anything where the moment is fleeting - sports, people, wildlife, etc ) then I would place speed of focussing the biggest factor in reliability. There's no advantage in having slow AF that's always accurate when you get home and have an SD card full of pics that that show the scene after that magical moment?

After all if you're into photography of landscapes or other static subjects then even manual focus is fine.

Don't get me wrong, I love a finely crafted landscape shot, but one of the things that most excites me about photography is going out and searching out fleeting moments in the world and trying to capture them.

Two things that that a big help to this are great ISO performance and great AF performance.

I still maintain Pentax need to raise their game in AF speed.

I think that is a fairly valid point. When everything else seems to be right up there or in front of the competition it would be daft not to concentrate on the weakest area, especially when its requirement is quite a big slice of the market
Dave

dcweather

Link Posted 28/01/2013 - 11:53
Blythman wrote:
dcweather wrote:
As the OP who has now having seen the result from Nikon 300D shot compared to my failed one could one of the experts suggest an improved technique or settings for me. I was, incidentally going from being focused on the ducks to them following take off so there wasn't a massive change in focal distance. My camera would still have been on AF centre spot. WOuld I be better off with lots of focal points and the 'C' setting. This was with DA*300 and K-30 by the way.
Thanks, Dave

Dave, in all likelihood you did nothing wrong.

A couple of examples which disappointed me the most because of the birds involved
1.....I was with both a Canon shooter and a Nikon shooter in late summer photographing a cuckoo. I got some great shots and was within 6 yards of it in the open. However it took off from a post and flew to another about 12-15 yards away. Both the other guys got fantastic in flight shots. I got a blur.

2.....Summer before I had my best views of a kingfisher. It even landed on the window ledge of the hide within 4 feet of me for a couple of seconds. Just before then it had been on a perch about 5 yards away, when it lifted, moved forward to about 3 yards. It hovered there for a second or two before diving for a fish. I've got a full frame abstract blue and orange picture.

After the cuckoo I thought very hard about selling up and was actively looking for a 7D and a Sigma 120-300 f2.8.

After much thought I decided to stick with Pentax because I want to photograph more than just wildlife and the K5 in my opinion is a better all round camera than the 7D. One example of that is my mate who takes fantastic wildlife images with his Canon 600mm f4 and 1.5 converter reckons the 7D is crap above ISO 800.

---------------------------------------------------
Thanks Alan, sounds like we are in about the same place then, really

philstaff

Link Posted 28/01/2013 - 12:01






I just use center point focus and usualy spot metering seems to work for me.

Regards Ian

Blythman

Link Posted 28/01/2013 - 17:06
Gulls are a great start for practising on Ian.
Alan


PPG
Flickr

NeilP

Link Posted 28/01/2013 - 23:34
Frogfish wrote:
NeilP wrote:
After recently trying and failing to focus on some flying Black headed gulls in decent light, I've decided the K-5 + D*300mm just inst up to action shots. Its fine for birds like red kites and a marsh harriers which fly slower, if they are not to close, but the AF speed and tracking cant track faster bird or slower ones that are too close sadly.

Neil. Gulls shouldn't be difficult, they are large and relatively slow moving. It's possible there is a problem with your technique or settings. Can you tell us how you hold your camera, whether you use a tripod/monopod and the settings you generally use for bird photography ?
I used the K5 and DA*300 for 2 years (with and without the AFA x1.7) and found it very good on larger birds, it was on smaller birds with frenetic feet, or flushed birds, where it had difficulty. In all cases a degree of anticipation is required though.

Here are some samples all with the K5 + DA*300









Actually black headed gulls chasing after bread can be quite fast! The K5 seems great at locking on on bird flying across shot a lot of the time (as long as they are not too close or fast), but coming towards you its seems to fail quite often. I noticed some benefit switch on my AF to the button but the K5 + DA*300mm will struggle to keep up with a duck or coot swimming fast towards the camera.

It also seems to struggle with birds/dragonflies far away or too close, so those frame filling shots can be a struggle, even if you follow it all the way in the AFc cant keep up or locks onto the body even when the head is in the centre of the spot - I'm guessing the AF spot/cross is too large to distinguish the head from the body. When photographing hovering dragonflies I had to pull the focus back to get the head in focus and not the body. That is if the dragonfly hovered long enough for the K5 to hunt through the 300mms focus range, despite it almost being in focus to start with....

Of course the High ISO performance is a trade off against other brands and when the K5 has focused, I've got some cracking shots where my canikon friends have had too little light/shutter speed.
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Frogfish

Link Posted 29/01/2013 - 08:39
Neil, don't feel too bad about missing shots of birds flying straight at you .. there are very few cameras (mostly all top pro models such as 1Dx or D3s/D4 that have the best AF motors around) that can get a high % of those shots in focus .... they are very difficult for the AF motor in consumer/prosumer cameras and probably burst mode (or if you know the direction the bird will take in advance then pre-focusing in MF & burst-mode) is your best chance.

You are spot on re. cross focus points being arge on the K5 series, this is a perpetual gripe amongst some users, it has it's pros and cons but for very small/tiny objects it's definitely not a pro ! If the dragonfly is hovering and you are almost in focus use MF to get it sharp (of course you must have re-mapped your AF to the AF-S button to do this otherwise subsequently depressing the shutter button will set off the AF again) !
http://frogfish.smugmug.com/ Pentax. Pentax DA*300/4, Cosina 55/1.2, Lens Baby Composer Pro & Edge 80, AFA x1.7, Metz 50 af1.
Nikon. D800. D600. Sigma 500/4.5, Nikon 300/2.8 VRII, Sigma 120-300/2.8, Zeiss Distagon ZF2 21/2.8, Zeiss Distagon ZF2 35/2.0, Sigma 50/1.4, Nikkor 85/1.8, Nikon TC20EIII, Nikon TC14EII, Kenko x1.4, Sigma 2.0
Last Edited by Frogfish on 29/01/2013 - 08:41

Jonathan-Mac

Link Posted 29/01/2013 - 22:05
I had a play with a Canon 6D as I went through the airport today and was very impressed with the speed and silence of the AF (it had a 24-105/4 mounted). It was clearly far superior to anything else I've used (K200D mainly) and it did make me pine for faster AF. At least I understand Pentax have improved this greatly in the last few years.

I still love my K200D though and my slowly growing DA limited collection won't work on Canon.
Pentax hybrid user - Digital K3, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X and Panasonic L digital
Fan of DA limited and old manual lenses

dcweather

Link Posted 29/01/2013 - 22:55
Jonathan-Mac wrote:
AF. At least I understand Pentax have improved this greatly in the last few years.


I would say my K-30 is better than my K-r but not that much, certainly not an order of magnitude although it is in live view should you ever need it..

cabstar

Link Posted 29/01/2013 - 23:37
dcweather wrote:
Jonathan-Mac wrote:
AF. At least I understand Pentax have improved this greatly in the last few years.


I would say my K-30 is better than my K-r but not that much, certainly not an order of magnitude although it is in live view should you ever need it..

Strange i thought the k-5 was better at af than the k-r which was superseded by another increase on the k-30. I guess it depends what you are shooting and with what glass.
PPG Wedding photography Flickr
Concert photography

Currently on a Pentax hiatus until an FF Pentax is released

Pheo

Link Posted 30/01/2013 - 12:59
One of the problems I have with telling how "fast" AF is, is when you use a Canon USM lens on a modern body, the focusing is silent, so I actually can't tell how quickly it is focusing, because I don't notice it doing it!

cabstar

Link Posted 30/01/2013 - 16:16
Pentax da* lenses are silent too...
PPG Wedding photography Flickr
Concert photography

Currently on a Pentax hiatus until an FF Pentax is released

toy_car_uk

Link Posted 30/01/2013 - 16:36
cabstar wrote:
dcweather wrote:
Quote:
AF. At least I understand Pentax have improved this greatly in the last few years.


I would say my K-30 is better than my K-r but not that much, certainly not an order of magnitude although it is in live view should you ever need it..

Strange i thought the k-5 was better at af than the k-r which was superseded by another increase on the k-30. I guess it depends what you are shooting and with what glass.

I frequently shoot ice hockey matches. I have used K100d, K-r and the K-30. There is massive leap from K100d to the K-r, and a significantly higher amount of shots in focus from the K-30 over the K-r when shooting the game.
My Flickr account, constructive criticism welcome.
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