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01-10-2009, 04:22 AM   #1
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Pentax AF vs Canon AF vs Nikon AF (In low light contitions)

How fast is pentax AF in low light contitons compared to Nikon and Canons AF?
Maybe the problem is in me, but I think that pentax AF sucks in low light, it takes to long to focus something and thats bad when you photograph people on a party.
Pentax FA 50mm F1.4 is f*cking slow even the kit lens is littlebit faster.

01-10-2009, 04:34 AM   #2
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What Pentax camera do you have?
Some of older are slower.
Compared to which Canon?
.
01-10-2009, 04:45 AM   #3
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I have a K10D and compared to Nikon D80 maybe and Canon 40D
01-10-2009, 07:17 AM   #4
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No experience with the D80 but the 40D will be significantly better from my experience.

01-10-2009, 08:30 AM   #5
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Pic attached was used @ A5 in the main climbing mag - THE WINNING SHOT so to say

Was the final in a series of 3 all taken in single shot mode, single & central af - so the action was stuffing fast

ISO 1600 ASA 1/40 sec, f 3.5 18mm, fill flash - 18-55 kit lens - extreme grunge lighting.

The pic here has been radically downsized to fit here.

The guy in the background using a Nikon D80 got no keepers and another with a Canon 450d chose not to shoot due the amount of chalk dust.

Hence I got paid - the others didn't - maybe they need to learn a little more
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01-10-2009, 08:45 AM   #6
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QuoteOriginally posted by karq Quote
How fast is pentax AF in low light contitons compared to Nikon and Canons AF?
Maybe the problem is in me, but I think that pentax AF sucks in low light, it takes to long to focus something and thats bad when you photograph people on a party.
Pentax FA 50mm F1.4 is f*cking slow even the kit lens is littlebit faster.
Buy a 17-70 SDM, or a 16-50 SMD. The old primes are very slow (same on some Canons and Nikons if they are screw drive).
01-10-2009, 11:05 AM   #7
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I don't find the 43/1.9 to be particularly slow. imho SDM doesn't speed things up, but it does make it quieter.

And yes, the problem could be "in me." I find that most of my photographic shortcomings end up being operator error rather than the fault of the equipment. But if you find a 40D or D80 to have superior AF in low light, and that is a critical criteria, then you should switch systems.

01-10-2009, 11:09 AM   #8
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My fa50 is veeery slow as well with the K20d. Almost painfully slow imho, so in very low light I sometimes switch to manual focus. Manual focus with low light is no good either, because you have to use very fast aperture and the dof is thin, thus you miss the focus anyway.

I just bought the o-me53 magnifying eyecup yesterday to get better manual focus.
01-10-2009, 11:39 AM   #9
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pasipasi, I'm not quite sure I understand what you're saying here.

If I set my K20 to Manual focus and my FA50 to auto aperture and stop it down on the camera, it stays open fully for focusing. This has no impact on my depth of field for the actual shot, which will be at the aperture I have chosen on camera.
01-10-2009, 11:42 AM   #10
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QuoteOriginally posted by nostatic Quote
I don't find the 43/1.9 to be particularly slow. imho SDM doesn't speed things up, but it does make it quieter.

And yes, the problem could be "in me." I find that most of my photographic shortcomings end up being operator error rather than the fault of the equipment. But if you find a 40D or D80 to have superior AF in low light, and that is a critical criteria, then you should switch systems.
That's what I did. I love the K20D but the AF was lacking in performance. I thought some lenses like the 30/1.4 were really fast, but the 1-series with 85/1.8 just blew my mind. It's INSTANT focus on everything in any light. But then again, it cost $8k new so not exactly a fair comparison. The 40D is not as fast, though quite respectable especially in crappier light situations. As I said, no experience with the D80, though my brother has a D40 which seems to be about the same as the K20D in AF performance, possibly a little stronger in low light.
01-10-2009, 01:50 PM   #11
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QuoteOriginally posted by karq Quote
How fast is pentax AF in low light contitons compared to Nikon and Canons AF?
Maybe the problem is in me, but I think that pentax AF sucks in low light, it takes to long to focus something and thats bad when you photograph people on a party.
Pentax FA 50mm F1.4 is f*cking slow even the kit lens is littlebit faster.
I just posted this but thought it might be relevant here -

Pentax are notorious for being slow in AF in low light levels - there is not that much improvement going from a K100D to even the current top of the line K20D -
here compared to some of the latest dSLRs from Canon, Nikon and Sony (read Minolta)



note the horizontal scale of the K20D is misaligned it should be the same as all the others.
(crops from certified test results from Popular Photogrphy)

The other well known brands are faster in lower light levels - but we are still talking in the order of about 3/4-1 sec to auto-focus - which is simply NOT fast enough to catch any action.

This is the misconception that faster automation is a panecea for ALL problems.

So how did photographers from years ago ever manage to capture action with manual focus lenses?
and there are lots of example out there including acknowledged masterpieces....
Almost ANY AutoFocus is faster than we can focus manually
- so why aren't we doing any better? ...

Did photographers from years ago with manual focus lenses wait to see the shot and then tried to focus to take the shot?
I know, that sounded absolutely ridiculous -
of course not, they pre-focussed their lenses and waited for the shot
then it was only literally tripping the shutter.

Use the same technique - Pre-Focus - by light half depression on the shutter button, hold that focus, re-compose, and wait for the shot - when the shot is seen, fully depress the shutter button, then the delay or shutter lag is less than 0.1 sec which is faster than human reaction time
or any AF from any brand ...... under any lighting conditions.
01-10-2009, 03:11 PM   #12
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QuoteOriginally posted by Lazaruscomeout Quote
pasipasi, I'm not quite sure I understand what you're saying here.

If I set my K20 to Manual focus and my FA50 to auto aperture and stop it down on the camera, it stays open fully for focusing. This has no impact on my depth of field for the actual shot, which will be at the aperture I have chosen on camera.
Right, but he specifically mentioned low light. Stopping down (much) is not usually an option photographing people in low light.
01-10-2009, 03:57 PM   #13
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QuoteOriginally posted by UnknownVT Quote
I just posted this but thought it might be relevant here -

Pentax are notorious for being slow in AF in low light levels - there is not that much improvement going from a K100D to even the current top of the line K20D -
here compared to some of the latest dSLRs from Canon, Nikon and Sony (read Minolta)



note the horizontal scale of the K20D is misaligned it should be the same as all the others.
(crops from certified test results from Popular Photogrphy)

The other well known brands are faster in lower light levels - but we are still talking in the order of about 3/4-1 sec to auto-focus - which is simply NOT fast enough to catch any action.

This is the misconception that faster automation is a panecea for ALL problems.

So how did photographers from years ago ever manage to capture action with manual focus lenses?
and there are lots of example out there including acknowledged masterpieces....
Almost ANY AutoFocus is faster than we can focus manually
- so why aren't we doing any better? ...

Did photographers from years ago with manual focus lenses wait to see the shot and then tried to focus to take the shot?
I know, that sounded absolutely ridiculous -
of course not, they pre-focussed their lenses and waited for the shot
then it was only literally tripping the shutter.

Use the same technique - Pre-Focus - by light half depression on the shutter button, hold that focus, re-compose, and wait for the shot - when the shot is seen, fully depress the shutter button, then the delay or shutter lag is less than 0.1 sec which is faster than human reaction time
or any AF from any brand ...... under any lighting conditions.
Quite right - skill

I did surf photography in the age when m/drives were really expensive and only did 3 shots/sec - could not afford so - how about callouses on the outer part of the thumb from winding the lever 5 hours a session.

Really - to be quite honest there are way tooo many whingers & whiners re: the Pentax system

D
01-10-2009, 04:31 PM   #14
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QuoteOriginally posted by karq Quote
How fast is pentax AF in low light contitons compared to Nikon and Canons AF?
Maybe the problem is in me, but I think that pentax AF sucks in low light, it takes to long to focus something and thats bad when you photograph people on a party.
Pentax FA 50mm F1.4 is f*cking slow even the kit lens is littlebit faster.
I can say for sure that
last October i went to a function with my K10D and 16-50 lens and got a whole hell of trouble, whole night with focusing issues
last month i went to the same venue, same lighting, same lens but with a K20D, and encountered no focusing issues
Hope this helps

Dave
01-10-2009, 04:56 PM   #15
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hi karq

i am a former pentax user, now i own a D80 with some good glass. true, the old pentax took it's sweet time while focusing, the D80 gives me satisfaction even in the nastiest illumination schemes. the 40 D should be even better. pentax is not famous for AF speed, but rather for AF consistency, precision of focus, at the expense of overall speed. i guess the photographer sometimes dictates the behaviour of the camera, so the guy with the D80 was probably a rookie or just plain misfortunate. in that picture, at 18 mm and f/3.5 the DOF is so large (78 feet according to dofmaster, 6 feet in front and 72 behind for a subject at 14 feet) that you don't even need AF, in fact, the camera probably could have focused whereever, you would have still gotten the shot. manual focus would have been a good ideea. i miss the colours that the pentax used to generate, switching was an unpleasant moment but i had no chouice.

Last edited by nicolaie; 01-10-2009 at 05:04 PM.
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