Slow AF?


johnriley

Link Posted 14/02/2010 - 10:16
Quote:
Is there any particular reason why Pentax's lenses are slow on the af front

I'm puzzled by this to some degree. Through the 1990s magazine reviews were full of praise for the snappy, cutting edge AF of Pentax cameras. I can say this because I've just been reading them all. Currently I have quite a few new Pentax lenses for my DSLRs and they all snap happily into focus. The only exceptions are very low light (too low for accurate manual focusing), some sorts of subjects (turn to manual for these) and sometimes fast moving wildlife (keep practising John!)

I was looking at a Tamron 70-300mm on a Canon 350D on Thursday and the focusing on this was positively lethargic. No zip at all.

It makes me wonder where this change in perception has originated as 99% of the time AF does what it days on the box.
Best regards, John

aminstar

Link Posted 14/02/2010 - 10:32
Hi John
just out of curiosity where did you find that quote?
It seems that AF speed is still a hugely contested subject,
Amin Photo Gallery

Mike-P

Link Posted 14/02/2010 - 10:35
johnriley wrote:


I'm puzzled by this to some degree. Through the 1990s magazine reviews were full of praise for the snappy, cutting edge AF of Pentax cameras.

Times move on, Pentax hasn't to any great degree where AF is concerned.
I took my 60-250mm to a local camera shop to try on a K-7 .. while I was there I had a go with a D300 .. absolutely no comparison, the Nikon was much faster. You are quoting magazine articles from the 1990s .. this is 2010.
No equipment list here but thanks for taking an interest. My Flickr

K10D

Link Posted 14/02/2010 - 10:39
I would say that the Pentax DSLR's are no worse than the upper range of othe marks. Indeed, often better. The real AF speeds are on the top Canikon models where the AF engine and "top" lenses perform very well.

All of that costs a lot more money.

Indeed, for my D700 to lock onto faster subjects with gauranteed sucess, it has to be programmed to fire without AF lock and by frame two or three it has locked on and stays locked. So tracking birds in flight will loose the first few frames only. Of course it is in machine gun mode for this.

I have yet to be genuinely let down by Pentax AF.

Is the glass always faster on the other side?

Regards

aminstar

Link Posted 14/02/2010 - 10:42
Mike-P wrote:

I took my 60-250mm to a local camera shop to try on a K-7 .. while I was there I had a go with a D300 .. absolutely no comparison, the Nikon was much faster. You are quoting magazine articles from the 1990s .. this is 2010.

Mike, have you ever stopped to think that may be if you require such a fast AF like the D300 has then perhaps its time for you to brush up your photographic skills again? stop doing macros and go and practise manual focusing by shooting birds in flight
Amin Photo Gallery
Last Edited by aminstar on 14/02/2010 - 10:46

Mike-P

Link Posted 14/02/2010 - 10:43
K10D wrote:


I have yet to be genuinely let down by Pentax AF.


I have on a few occasions but I put that down to the K10D whith its scratched sensor, 40,000 + shutter actuations and designer red tape memory card door lock. (oh and me).
No equipment list here but thanks for taking an interest. My Flickr

aminstar

Link Posted 14/02/2010 - 10:45
K10D wrote:

Indeed, for my D700 to lock onto faster subjects with gauranteed sucess, it has to be programmed to fire without AF lock and by frame two or three it has locked on and stays locked. So tracking birds in flight will loose the first few frames only. Of course it is in machine gun mode for this.

I have yet to be genuinely let down by Pentax AF.

Is the glass always faster on the other side?

Regards

I have seen some people with D300 catching birds in flight without putting the camera in machine gun mode. In fact sometime ago I remember a thread where Danny (unlocker) was mentioning about being next to someone using a Nikon if I am not mistaken during a sports event just next to him and making every single shot count and she/he didnt have the camera on machine gun mode.

Oh by the way, what's the price difference between K7 and D300? Sorry I haven't been accompanying any prices lately so perhaps someone could elucidate it for me
Amin Photo Gallery
Last Edited by aminstar on 14/02/2010 - 10:48

johnriley

Link Posted 14/02/2010 - 10:49
Amin, the quote was from a comment on another thread today. Rather than divert the thread I thought it was interesting enough to challenge and explore the preconception.

Mike, the point was that at one time not so long ago (10 years) Pentax was considered cutting edge so why not in 2010 when AF speed does not seem so different from others, and I have seen that the others can actually be much slower sometimes.

There is a physical limit as to how fast AF can be and we seem to be close to it in many circumstances.
Best regards, John

Mike-P

Link Posted 14/02/2010 - 10:50
aminstar wrote:


I have seen some people with D300 catching birds in flight without putting the camera in machine gun mode. In fact sometime ago I remember a thread where Danny (unlocker) was mentioning about being next to someone using a Nikon if I am not mistaken during a sports event just next to him and making every single shot count and she/he didnt have the camera on machine gun mode

There is a thread on another forum where someone with a 7D took their dog to a field and then let him run some distance towards them while taking pics at 7fps (the hardest thing for AF tracking apparently). It did very well getting around 90% in focus. I have had old age pensioners walking towards me and my K10D wouldnt lock on
No equipment list here but thanks for taking an interest. My Flickr

K10D

Link Posted 14/02/2010 - 10:50
aminstar wrote:
K10D wrote:

Indeed, for my D700 to lock onto faster subjects with gauranteed sucess, it has to be programmed to fire without AF lock and by frame two or three it has locked on and stays locked. So tracking birds in flight will loose the first few frames only. Of course it is in machine gun mode for this.

I have yet to be genuinely let down by Pentax AF.

Is the glass always faster on the other side?

Regards

I have seen some people with D300 catching birds in flight without putting the camera in machine gun mode. In fact sometime ago I remember a thread where Danny (unlocker) was mentioning about being next to someone using a Nikon if I am not mistaken during a sports event just next to him and making every single shot count and she/he didnt have the camera on machine gun mode

I hav not used the mode but tried to remember the gist of it from a Ken Rockwell article.

If the D300 uses the same AF engine as the D700/D3 then yup, it's quick.

"what if we had 150MP sesnors, just stick a 50mm lens on and crop into the bottomless resolution" hmm now theres a thought for 2012. No focus issues with a good DOF.

Cheers

Regards

ChrisA

Link Posted 14/02/2010 - 10:56
aminstar wrote:
In fact sometime ago I remember a thread where Danny (unlocker) was mentioning about being next to someone using a Nikon if I am not mistaken during a sports event just next to him and making every single shot count and she/he didnt have the camera on machine gun mode

You can't really tell until you get the pictures on to the computer.

I was on a boat trip last year and the seagulls were flying circuits round the boat for ages. I took about 100 shots, and on the LCD lots of them looked great.

When I looked at them properly though, only a very few were usable.

For aircraft in flight, the K10's AF is more than adequate. For birds, I really don't think it is. Birds change direction and speed much more suddenly than aircraft, and they're a lot closer, so a small change of direction will have a proportionately large effect on distance.

I can't imagine anything that places more demands on the AF system than birds in flight.
.
Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
.

aminstar

Link Posted 14/02/2010 - 11:11
Mike-P wrote:
I have had old age pensioners walking towards me and my K10D wouldnt lock on

Mike
if you can't lock on an old age pensioner walking towards you even with your cracked memory door K10 then definitely you are getting old and your hands are not as steady as they used to be like when you took this shots like these ones


I agree about the 7D fast AF, in fact its not the only one that I have come across with experiments like the running dog. But people's priorities are different, and this is an old age debate already, for many people super fast AF doesn't really come top of the list. I for one am too lazy to adapt and try other means to acquire focusing with a slower AF system so unfortunately had to move. But I have to say that time played a huge part in this for me, if I had got into photography a few months later and had bought my kit after the price hikes then I certainly wouldn't have done it. As it was I off loaded all my kit at a premium and didnt spend anything extra in getting all that I needed in the other system, and still have the DA*50-135 as a bonus that is still to be sold. But truth be said, I miss the good old days of pentax oh the memories, particularly of some heated debates around here
Amin Photo Gallery

K10D

Link Posted 14/02/2010 - 11:19
Quote:
But truth be said, I miss the good old days of pentax oh the memories, particularly of some heated debates around here

Hey, only cryogenic comments these days.

Regards

Mike-P

Link Posted 14/02/2010 - 11:20
aminstar wrote:
But truth be said, I miss the good old days of pentax oh the memories, particularly of some heated debates around here

The good old days?
You only had a Pentax for around 12 months

Although if you had to post my picture twice maybe its YOUR eyesight going
No equipment list here but thanks for taking an interest. My Flickr
Last Edited by Mike-P on 14/02/2010 - 11:22

K10D

Link Posted 14/02/2010 - 11:22
Mike-P wrote:
aminstar wrote:
But truth be said, I miss the good old days of pentax oh the memories, particularly of some heated debates around here

The good old days?
You only had a Pentax for around 12 months

Then better to have used and left than never used at all?

Regards
Add a Comment
You must be registered or logged-in to comment.