Pentax AF really need fixing

**Ash** · 05-03-2011, 05:40 PM

Originally posted by Wheatfield

He makes a good point though.
One of the things I have found since I started taking pictures some 40 years ago is that DOF is less relevant than sharpness, and that lenses are often (I would go so far as to say always, but someone would find an example which proves the other 99.99999999% untrue in their eyes) sharper stopped down a little bit.
For me, an f/1.4 lens is more for a brighter screen than anything else.

This, as well as giving a slight edge for low-light focusing, is a definite virtue of having faster lenses. But they are still better stopped down in *most* cases, not just for image quality, but for getting enough of the subject in focus...

I have tried to argue the 'f/1.4 is no great DoF disadvantage to f/2' point before but appreciate that there will always be some who simply desire the thinnest of DoF (such as out A/K 50/1.2 owners who use it at f/1.2

)...

Eruditass · 05-03-2011, 06:20 PM

Originally posted by Ash

I have tried to argue the 'f/1.4 is no great DoF disadvantage to f/2' point before but appreciate that there will always be some who simply desire the thinnest of DoF (such as out A/K 50/1.2 owners who use it at f/1.2

)...

Focus out to 20 feet with a normal lens and the DoF isn't razor thin...

Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring):

Ryan Brenizer

Sean Molin

Sharpness from stopping down is another story and I agree.

DogLover · 05-03-2011, 06:33 PM

Originally posted by Wheatfield

I often wonder if they are more about making a point than about making photographs.
Quite honestly, most of the thin DOF images I've seen here would be vastly improved with a little more overall sharpness, and accepting a bit more, but probably not really noticeable, DOF.

I think this way, too. I almost never shoot at less than f/2 for this very reason.

Smeggypants · 05-03-2011, 07:06 PM

Originally posted by Siegfried

Dudes, the very shallow DOF is just a photographic tool like.......

Actually in a lot of lighting levels and scenes narrow DOF is the way we actually see things with our own eyes and probably accounts for why it we find it pleasurable or natural.

You don't normally notice it becuase you are concentrating on the subject and your eyes AF as you flick from subject to subject at different distances.

Tommot1965 · 05-03-2011, 07:57 PM

Originally posted by Ash

There are indeed a few little niggles that I'm sure Pentax could solve with simple firmware updates - the LED AF-assist in external flash shooting is one, as well as improving low light front focusing accuracy. I'm hopeful they'll come to the party with some of these.

OCD is obsessive-compulsive disorder, an overused term merely to describe in everyday language someone who obsesses over detail, thrives on order and struggles with imperfection. Strictly speaking, an OCD-'sufferer' goes to the extent of having the obsessions and compulsions affect and take over their lives.

Ash

how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light .....

Smeggypants · 05-03-2011, 08:23 PM

Originally posted by Tommot1965

Ash

how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light .....

I fond the AF lamp consistent in 1.02 and below. 1.03 it is inconsistent. This is the same on all 3 K-5s I have used

rfortson · 05-03-2011, 08:34 PM

Originally posted by Christine Tham

Another example, the camera is focused on the scarf of the woman on the right, but her friend on the left - inches away from her - is out of focus - taken on the A135mm at f2.8:

I'm sure it could be argued that creatively this is a bad photo - perhaps her friend should have been focused as well, but I personally really liked the way this shot came out.

The difference in focus between the two women are much more obvious when the picture is blown up, or printed on a larger surface.

Hi Christine, I won't presume to comment on your photographs other than to say that they don't support the OP's claim that outdoors, wide open, the AF stinks. Your shots are perfectly in focus where you intended. That's been my experience as well.

Skymist · 05-03-2011, 11:39 PM

Originally posted by Croc

oh i do close it down a bit, in general i'm very happy with pentax, i got well over 100K keepers from just last few years with pentax gear but seeing how old canon with f1.4 lens had no such problems at all this makes me bit mad, pentax gear is too good to be ruined by issue like this.

That's interesting. Before I got my K-5 I got a Canon 550D with a Canon F/1.4 50mm lens. I had a lot of problems getting the AF to work well with the lens wide open. Eventually I gave the camera to my daughter and got my K-5, plus a Zeiss T* f/1.4 50mm. It focused more reliably with the f1.4 than the Canon, most of the time. Even it was not perfect by any means. So I rely on Liveview a lot, and have worked on training my eye with the viewfinder better. But the point is that the two cameras really gave me the same experience with autofocus on similar fast lenses, except that the K-5 was perhaps a little more accurate (but a bit slower) in all but the dimmest light, at which point the two cameras were fairly similar. All testing done with firmware 1.03.

**Fontan** · 05-03-2011, 11:44 PM

Originally posted by Skymist

That's interesting. Before I got my K-5 I got a Canon 550D with a Canon F/1.4 50mm lens. I had a lot of problems getting the AF to work well with the lens wide open. Eventually I gave the camera to my daughter and got my K-5, plus a Zeiss T* f/1.4 50mm. It focused more reliably with the f1.4 than the Canon, most of the time. Even it was not perfect by any means. So I rely on Liveview a lot, and have worked on training my eye with the viewfinder better. But the point is that the two cameras really gave me the same experience with autofocus on similar fast lenses, except that the K-5 was perhaps a little more accurate (but a bit slower) in all but the dimmest light, at which point the two cameras were fairly similar. All testing done with firmware 1.03.

Hm . . . . I am not understanding this correctly. Zeiss T* 50/1.4 is manual focus only.

JohnBee · 05-03-2011, 11:51 PM

Originally posted by Eruditass

Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring):.

But wouldn't the brenizer method qualify as post processing? I was under the impression that it was a fancy term for panoramic photography.
Anyways, if that were the case, my tendency would be to consider PP to be a more lucrative approach to sequential frame photography. or... better yet... invest in a 645D and lean on the FOV advantages as an alternative.

Oh and great compositions btw. they really work with the colors and settings!

Siegfried · 05-04-2011, 03:51 AM

Ash,
Understood, I feel myself a bit confused I haven't met that term before.

Eruditass,
you made my day. I've studied K-5 manual twice (I love reading manuals, honestly) but I missed that feature there.

Zig

**Ash** · 05-04-2011, 04:03 AM

Originally posted by Tommot1965

Ash

how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light .....

I've had no noticeable issues with my LED lamp to date for focusing to relatively close distances (up to perhaps about 8m). It helps the K-5 focus fast and reliably. I haven't had Smeggy's problems crop up to now. But I agree, when the light is questionable and the lamp doesn't light up, it can prove to be somewhat more difficult, but not too much - the K-5 doesn't do badly without the AF lamp in those borderline situations.

Where I would like to see a firmware update, I've mentioned it before, is to permit the AF lamp to do its job even when an external flash is mounted, so as to circumvent the flash's slow and unreliable AF spotbeam function.

garyk · 05-04-2011, 04:22 AM

I was out today with a 2.8 in low light, sunny day but under the canopy, and the Af only hit 3 times out of 20. I will see if i deleted the photos or not. If not i will post and add a link. Funny the 300mm 2.8 lens will AF all over the place. But the same setting the 500mm 4.5 is spot on. I was going to do some tests today but was to busy. As much as i hate too I agree with Croc.
It is a problem with where it focuses for sure. The larger DOF saves the shots with 4.5 and above but f 2.8 is just useless. At first i thought the same thing. Sigma is the pits, but with the 300 in the service center again. I have to throw up my hands and move on to cannon.. What a shame.

I've been critical about testing. but this is getting just funny how bad Pentax is. For me only I have no choice. It is either switch or not post quality photos.

I've said it before but again. I will not buy another Pentax lens. But will pray for a good camera.

jake14mw · 05-04-2011, 06:12 AM

Originally posted by Eruditass

Focus out to 20 feet with a normal lens and the DoF isn't razor thin...

Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring):

Sharpness from stopping down is another story and I agree.

Eruditass,

Those pics you posted are great. Not sure if I got your grammer correct. You meant that you used the Brenzier method for those pictures which gave much shallower DOF than one photo at 1.4 could give, correct? Thanks for posting, I never heard this term before, and looked it up quickly. So, the summary of the method is, if you want a wide shot with shallow DOF, since DOF is shallower at longer focal lengths, use a longer focal length lens and take multiple shots, and stitch them together to get the wider perspective but take advantage of the shallow DOF?

**Ash** · 05-04-2011, 06:12 AM

Gary, under good lighting conditions you're not getting AF to lock on, or is it locking on way off the mark? This is different to what I thought would be happening. Seems to me that the troublesome K-5s have different issues unique to each camera. This will be more difficult to resolve with Pentax, but I'd like to know more about your own situation Gary. You have the Sigma 300/2.8 and 500/4.5 - any other lenses you've test driven on your K-5?

05-03-2011, 06:20 PM	#92
Eruditass Veteran Member Join Date: Jul 2009 Photos: Gallery Posts: 2,207	Originally posted by Ash I have tried to argue the 'f/1.4 is no great DoF disadvantage to f/2' point before but appreciate that there will always be some who simply desire the thinnest of DoF (such as out A/K 50/1.2 owners who use it at f/1.2 )... Focus out to 20 feet with a normal lens and the DoF isn't razor thin... Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring): Ryan Brenizer Sean Molin Sharpness from stopping down is another story and I agree. Last edited by Eruditass; 06-02-2011 at 12:44 PM.

05-03-2011, 11:51 PM	#100
JohnBee Veteran Member Join Date: Sep 2008 Location: Newrfoundland Photos: Albums Posts: 4,667	Originally posted by Eruditass Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring):. But wouldn't the brenizer method qualify as post processing? I was under the impression that it was a fancy term for panoramic photography. Anyways, if that were the case, my tendency would be to consider PP to be a more lucrative approach to sequential frame photography. or... better yet... invest in a 645D and lean on the FOV advantages as an alternative. Oh and great compositions btw. they really work with the colors and settings! Last edited by JohnBee; 05-03-2011 at 11:56 PM.

05-04-2011, 04:03 AM	#102
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by Tommot1965 Ash how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light ..... I've had no noticeable issues with my LED lamp to date for focusing to relatively close distances (up to perhaps about 8m). It helps the K-5 focus fast and reliably. I haven't had Smeggy's problems crop up to now. But I agree, when the light is questionable and the lamp doesn't light up, it can prove to be somewhat more difficult, but not too much - the K-5 doesn't do badly without the AF lamp in those borderline situations. Where I would like to see a firmware update, I've mentioned it before, is to permit the AF lamp to do its job even when an external flash is mounted, so as to circumvent the flash's slow and unreliable AF spotbeam function. Last edited by Ash; 05-04-2011 at 04:10 AM.

05-04-2011, 04:22 AM	#103
garyk Inactive Account Join Date: Feb 2010 Photos: Gallery Posts: 488	I was out today with a 2.8 in low light, sunny day but under the canopy, and the Af only hit 3 times out of 20. I will see if i deleted the photos or not. If not i will post and add a link. Funny the 300mm 2.8 lens will AF all over the place. But the same setting the 500mm 4.5 is spot on. I was going to do some tests today but was to busy. As much as i hate too I agree with Croc. It is a problem with where it focuses for sure. The larger DOF saves the shots with 4.5 and above but f 2.8 is just useless. At first i thought the same thing. Sigma is the pits, but with the 300 in the service center again. I have to throw up my hands and move on to cannon.. What a shame. I've been critical about testing. but this is getting just funny how bad Pentax is. For me only I have no choice. It is either switch or not post quality photos. I've said it before but again. I will not buy another Pentax lens. But will pray for a good camera. Last edited by garyk; 05-04-2011 at 04:29 AM.

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05-03-2011, 05:40 PM	#91
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Originally posted by Wheatfield He makes a good point though. One of the things I have found since I started taking pictures some 40 years ago is that DOF is less relevant than sharpness, and that lenses are often (I would go so far as to say always, but someone would find an example which proves the other 99.99999999% untrue in their eyes) sharper stopped down a little bit. For me, an f/1.4 lens is more for a brighter screen than anything else. This, as well as giving a slight edge for low-light focusing, is a definite virtue of having faster lenses. But they are still better stopped down in most cases, not just for image quality, but for getting enough of the subject in focus... I have tried to argue the 'f/1.4 is no great DoF disadvantage to f/2' point before but appreciate that there will always be some who simply desire the thinnest of DoF (such as out A/K 50/1.2 owners who use it at f/1.2 )...

05-03-2011, 06:33 PM	#93
DogLover Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 2,054	Originally posted by Wheatfield I often wonder if they are more about making a point than about making photographs. Quite honestly, most of the thin DOF images I've seen here would be vastly improved with a little more overall sharpness, and accepting a bit more, but probably not really noticeable, DOF. I think this way, too. I almost never shoot at less than f/2 for this very reason.

05-03-2011, 07:06 PM	#94
Smeggypants Veteran Member Join Date: Sep 2010 Posts: 1,536	Originally posted by Siegfried Dudes, the very shallow DOF is just a photographic tool like....... Actually in a lot of lighting levels and scenes narrow DOF is the way we actually see things with our own eyes and probably accounts for why it we find it pleasurable or natural. You don't normally notice it becuase you are concentrating on the subject and your eyes AF as you flick from subject to subject at different distances.

05-03-2011, 07:57 PM	#95
Tommot1965 Veteran Member Join Date: Sep 2010 Location: Perth Western Australia Photos: Gallery \| Albums Posts: 1,026	Originally posted by Ash There are indeed a few little niggles that I'm sure Pentax could solve with simple firmware updates - the LED AF-assist in external flash shooting is one, as well as improving low light front focusing accuracy. I'm hopeful they'll come to the party with some of these. OCD is obsessive-compulsive disorder, an overused term merely to describe in everyday language someone who obsesses over detail, thrives on order and struggles with imperfection. Strictly speaking, an OCD-'sufferer' goes to the extent of having the obsessions and compulsions affect and take over their lives. Ash how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light .....

05-03-2011, 08:23 PM	#96
Smeggypants Veteran Member Join Date: Sep 2010 Posts: 1,536	Originally posted by Tommot1965 Ash how do you find the Af assist lamp ..when I had my K5 it was inconsistent when it would come on or not ....I found that frustrating ..if pentax fixed that alone I reckon it would make a big difference to the AF abilities in low light ..... I fond the AF lamp consistent in 1.02 and below. 1.03 it is inconsistent. This is the same on all 3 K-5s I have used

05-03-2011, 08:34 PM	#97
rfortson Veteran Member Join Date: Sep 2006 Location: Houston TX Photos: Gallery Posts: 2,129	Originally posted by Christine Tham Another example, the camera is focused on the scarf of the woman on the right, but her friend on the left - inches away from her - is out of focus - taken on the A135mm at f2.8: I'm sure it could be argued that creatively this is a bad photo - perhaps her friend should have been focused as well, but I personally really liked the way this shot came out. The difference in focus between the two women are much more obvious when the picture is blown up, or printed on a larger surface. Hi Christine, I won't presume to comment on your photographs other than to say that they don't support the OP's claim that outdoors, wide open, the AF stinks. Your shots are perfectly in focus where you intended. That's been my experience as well.

05-03-2011, 11:39 PM	#98
Skymist Senior Member Join Date: Apr 2011 Location: Monterey Bay, Callifornia Posts: 107	Originally posted by Croc oh i do close it down a bit, in general i'm very happy with pentax, i got well over 100K keepers from just last few years with pentax gear but seeing how old canon with f1.4 lens had no such problems at all this makes me bit mad, pentax gear is too good to be ruined by issue like this. That's interesting. Before I got my K-5 I got a Canon 550D with a Canon F/1.4 50mm lens. I had a lot of problems getting the AF to work well with the lens wide open. Eventually I gave the camera to my daughter and got my K-5, plus a Zeiss T* f/1.4 50mm. It focused more reliably with the f1.4 than the Canon, most of the time. Even it was not perfect by any means. So I rely on Liveview a lot, and have worked on training my eye with the viewfinder better. But the point is that the two cameras really gave me the same experience with autofocus on similar fast lenses, except that the K-5 was perhaps a little more accurate (but a bit slower) in all but the dimmest light, at which point the two cameras were fairly similar. All testing done with firmware 1.03.

05-03-2011, 11:44 PM	#99
Fontan Site Supporter Join Date: Jan 2011 Location: 5th floor Posts: 1,610	Originally posted by Skymist That's interesting. Before I got my K-5 I got a Canon 550D with a Canon F/1.4 50mm lens. I had a lot of problems getting the AF to work well with the lens wide open. Eventually I gave the camera to my daughter and got my K-5, plus a Zeiss T* f/1.4 50mm. It focused more reliably with the f1.4 than the Canon, most of the time. Even it was not perfect by any means. So I rely on Liveview a lot, and have worked on training my eye with the viewfinder better. But the point is that the two cameras really gave me the same experience with autofocus on similar fast lenses, except that the K-5 was perhaps a little more accurate (but a bit slower) in all but the dimmest light, at which point the two cameras were fairly similar. All testing done with firmware 1.03. Hm . . . . I am not understanding this correctly. Zeiss T* 50/1.4 is manual focus only.

05-04-2011, 03:51 AM	#101
Siegfried Senior Member Join Date: Apr 2010 Location: in a middle of nowhere Photos: Gallery \| Albums Posts: 165	Ash, Understood, I feel myself a bit confused I haven't met that term before. Eruditass, you made my day. I've studied K-5 manual twice (I love reading manuals, honestly) but I missed that feature there. Zig

05-04-2011, 06:12 AM	#104
jake14mw Veteran Member Join Date: Jan 2008 Location: Connecticut, USA Posts: 977	Originally posted by Eruditass Focus out to 20 feet with a normal lens and the DoF isn't razor thin... Some extreme examples with way shallower than what f1.4 would acheive with the brenizer method (all standard lens optical blur, no T/S or post process blurring): Sharpness from stopping down is another story and I agree. Eruditass, Those pics you posted are great. Not sure if I got your grammer correct. You meant that you used the Brenzier method for those pictures which gave much shallower DOF than one photo at 1.4 could give, correct? Thanks for posting, I never heard this term before, and looked it up quickly. So, the summary of the method is, if you want a wide shot with shallow DOF, since DOF is shallower at longer focal lengths, use a longer focal length lens and take multiple shots, and stitch them together to get the wider perspective but take advantage of the shallow DOF?

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05-04-2011, 06:12 AM	#105
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	Gary, under good lighting conditions you're not getting AF to lock on, or is it locking on way off the mark? This is different to what I thought would be happening. Seems to me that the troublesome K-5s have different issues unique to each camera. This will be more difficult to resolve with Pentax, but I'd like to know more about your own situation Gary. You have the Sigma 300/2.8 and 500/4.5 - any other lenses you've test driven on your K-5?