Four years, three cameras and still fighting AF reliability

Started Jul 9, 2010 | Discussions
Alfisti Veteran Member • Posts: 6,649
Four years, three cameras and still fighting AF reliability

Four years ago I bought a K100D, kit lenses and an FA50/1.4, I was a happy chappy and new to the DSLR world as many of us were at the time. To cut a long story short, it took me three to six infuriating months to figure out that under incandescent light the cameras AF system goes a little bonkers and despite just dropping $1500 on the set up, I could not trust the AF indoors under said lighting.

I worked around it for a time, went on a long holiday in 08 and mostly caught keepers with my 12-24, 18-250 and 77 ltd. I also bought an FA35/2 that was razor sharp.

Decided to upgrade to a 20D, amongst other reasons for the ability to set AF bias for individual lenses … excellent I thought. I was never really happy with the lack of consistency using the 77 and the 35, well I never once took a decent image with the 35.

I just got my hands on a K7, I have a few issues with the thing such as a very washed out LCD screen (is it just me??) and slow write times to my SD card (again is it just me???), but overall quite pleased with the smaller unit.

Again though, I cannot for the LIFE of me take a half decent image with the FA35. So I grab the 77 and the same thing, after two full days of futsing around is appears the camera is severely back focusing with both lenses, even outdoors.

On paper this should not be an issue as I can just adjust the AF bias. Thing is, it’s the sheer inconsistency that drives me ABSOLUTELY AND TOTALLY INSANE. I’ll aim at one object and it’s bang on, the next and it’s FF, the next and it’s back focused …… short distances it FF, long it BF ….. it’s a complete and utter crap shoot to be totally honest.

I am in the process of determining if it’s just FA lenses but my DA lenses are slow so it’s hard to tell.

Not really sure why I wrote this diatribe, I mean pentax really suit me with the smaller form factor and nice to hold FA primes but dear me, I can only take so much of this. The 77 retails for some $1k and I cannot rely on the camera to nail focus at all.

Four years later and still disappointed.

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laurynas Regular Member • Posts: 287
Re: Four years, three cameras and still fighting AF reliability

bad luck

but turn off all lens corrections and the issue of "slow card" will be gone.

kmac1036 Regular Member • Posts: 323
Re: Four years, three cameras and still fighting AF reliability

what types of things are you shooting? how is the af set on your bodies? got some img samples?

& you understand that af needs contrast to focus, correct? flat walls & really low light, the camera will hunt a lot or not lock focus.

also, what SD cards are u using? cheap class 2 or 4 will have slow read/write times. my k200d is slower no matter which card I use tho..
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gertce
gertce Regular Member • Posts: 377
Re: Four years, three cameras and still fighting AF reliability

Any sample pics that went completely wrong?

Do remember that the AF point are much larger than the red dots you see in the viewfinder. On my K20D the center dot almost completely fills the spot meter circle on the focus screen.

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OP Alfisti Veteran Member • Posts: 6,649
Re: Four years, three cameras and still fighting AF reliability

kmac1036 wrote:

what types of things are you shooting? how is the af set on your bodies? got some img samples?

Everything and anything. A ball on the lawn, a bolt protuding from a wall, my wife's face, random objects placed on concrete (perfect for picking up focus as the object has gobs on contrast with the concrete). Inconsistant, inconsistant, inconsistant.

& you understand that af needs contrast to focus, correct? flat walls & really low light, the camera will hunt a lot or not lock focus.

Yes, I am an experienced and rational user.

also, what SD cards are u using? cheap class 2 or 4 will have slow read/write times. my k200d is slower no matter which card I use tho..

Class 6 that were much faster on my 20D.

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viking79
viking79 Forum Pro • Posts: 14,156
Re: Four years, three cameras and still fighting AF reliability

Alfisti wrote:

Four years ago I bought a K100D, kit lenses and an FA50/1.4, I was a happy chappy and new to the DSLR world as many of us were at the time. To cut a long story short, it took me three to six infuriating months to figure out that under incandescent light the cameras AF system goes a little bonkers and despite just dropping $1500 on the set up, I could not trust the AF indoors under said lighting.

I worked around it for a time, went on a long holiday in 08 and mostly caught keepers with my 12-24, 18-250 and 77 ltd. I also bought an FA35/2 that was razor sharp.

Decided to upgrade to a 20D, amongst other reasons for the ability to set AF bias for individual lenses … excellent I thought. I was never really happy with the lack of consistency using the 77 and the 35, well I never once took a decent image with the 35.

I just got my hands on a K7, I have a few issues with the thing such as a very washed out LCD screen (is it just me??) and slow write times to my SD card (again is it just me???), but overall quite pleased with the smaller unit.

This is you, it has no issue writing 20 MB/s using my SD Extreme III cards. Try a different memory card?

I can't comment much on your focus issues. Overall I have been happy with the K-7 and it has been very consistent, even with lenses like the Sigma 30mm f/1.4. As long as I don't focus-recompose at close distances (that throws it off). At 250mm with my DA*60-250 is the only place I have had issues, which was because it was rear focusing a bit.

Eric

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OP Alfisti Veteran Member • Posts: 6,649
Re: Four years, three cameras and still fighting AF reliability

Here's the thing with sample pics, you'll get all the apologists saying "oh well you need to use a tripod and do this and do that". Well no, when i do that and correct the bias under those conditions I go out and shoot and it's inconsistant, inconsistant, inconsistant. I just cannot trust it at all.

I keep hearing that the AF point is larger than they look, honestly I just don't care.

gertce wrote:

Any sample pics that went completely wrong?

Do remember that the AF point are much larger than the red dots you see in the viewfinder. On my K20D the center dot almost completely fills the spot meter circle on the focus screen.

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MightyMike Forum Pro • Posts: 40,698
Re: Four years, three cameras and still fighting AF reliability

You got to wonder after 3 cameras if its maybe the photographer, either doing something wrong or having horribly terrible bad luck.

Maybe we should meet up again and test cameras/equipment to see if i get the same results

as for write time, could it be you have distortion/CA correction turned on? and the screen looking washed out what is it set to for brightness? and if none of that is wrong then take it in and get a replacement K-7 as they might have sold you a dud.
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WildSammy Senior Member • Posts: 1,070
Re: Four years, three cameras and still fighting AF reliability

I had the same problem with AF inconsistency with my FA31, FA77 and F50 vs my K20D body. Also I had tested the lenses on friends K20D and AF was spot on all the time. So I decided to send body with all my lenses to service. I hope they will fix it right. I wish you good luck with your setup, but when are you unsatisfied with AF as are you describing try to send your equipment for adjustment to service too. That's my advice. As for the Pentax AF I hope the new SAFOX which is used in 645D and will be used in future APS-C bodies will help to be more reliable and faster when the optical path is optimized.
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OP Alfisti Veteran Member • Posts: 6,649
Re: Four years, three cameras and still fighting AF reliability

It's not a bad idea TBH, maybe it is me though short of pointing the red dot at an abject, half pressing the shutter then slowing releasing I am not too sure what else there is to f$%^ up TBH.

MightyMike wrote:

You got to wonder after 3 cameras if its maybe the photographer, either doing something wrong or having horribly terrible bad luck.

Maybe we should meet up again and test cameras/equipment to see if i get the same results

as for write time, could it be you have distortion/CA correction turned on? and the screen looking washed out what is it set to for brightness? and if none of that is wrong then take it in and get a replacement K-7 as they might have sold you a dud.
--
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jamesm007 Veteran Member • Posts: 5,663
Re: Four years, three cameras and still fighting AF reliability

Yep perfect AF is the number one problem/complaint user or camera or lens which is it. It can be all 3 and its very hard to differentiate it, especially for others just reading. In this case I will assume its not the user. So it leaves the camera and lens. Since you have had the same problem with 3 bodies why not send them in to be checked and calibrated? If you read other forums the grass in not really greener on the other side, that is until they make a forum for EVIL type cameras that end 2 of the 3 problems, and only leaves the users as a problem. Contrast AF on the sensor can't be beat for accuracy and is immune to BF/FF because focus is done on the sensor and not through mirrors bouncing light and AF modules that must be in perfect sysnc to 15Mp super high resolution cameras! Its one reason many want them. I don't, I want a OVF... but???

My K20D has fallen a bit toward BF, but I am able to correct it through the AF fine tuning. So all my lens are spot on wide open. But there is no doubt over time AF losses some of its factory accuracy and hence why Pentax recommends we send in our dSLRs every year or two for a checkup and calibration. Very complex and precession machines we have with dSLRs and manufacturers are mass producing them cheap... Film was much more forgiving than digital sensors with respect to BF/FF, its an old outdated AF system (SLR) applied to very high resolution sensors that need extremely high AF precision and maintain that accuracy for years, what to do?

It is possible to make a self aligning sensor, that would with a press of the button align itself perfect to the AF module. But lens can cause FF/BF and that can also be fixed with alignment using contrast detection on the sensor. And doing that would be all you need and would not need to align the sensor to the AF module all the time, just one sensor calibration then calibrate each lens. It can be done, I could design the concept, but it would cost money. But! It would keep SLR alive and negate many of the benefits of EVILS over SLR. SLR with self calibrating sensor/lens functions!
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OP Alfisti Veteran Member • Posts: 6,649
Re: Four years, three cameras and still fighting AF reliability

I don't mind paying a bit to do this TBH, i have a holiday in 6 weeks though so it would be tight.

WildSammy wrote:

I had the same problem with AF inconsistency with my FA31, FA77 and F50 vs my K20D body. Also I had tested the lenses on friends K20D and AF was spot on all the time. So I decided to send body with all my lenses to service. I hope they will fix it right. I wish you good luck with your setup, but when are you unsatisfied with AF as are you describing try to send your equipment for adjustment to service too. That's my advice.
--
S.

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MightyMike Forum Pro • Posts: 40,698
Re: Four years, three cameras and still fighting AF reliability

Fair, it should be simple but getting together will either have another person backing you up and saying yes you've got the problem you describe or you might get another perspective on the issue... you know how to contact me, i should be available this weekend, but i've got to go to work now... i have lenses, you have lenses i have a K-7 and K-x we can test 3 different camera bodies all lenses and see if we can't find a conclusion.
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Gerry Winterbourne Forum Pro • Posts: 18,208
Re: Four years, three cameras and still fighting AF reliability

Alfisti wrote:

I just got my hands on a K7, I have a few issues with the thing such as a very washed out LCD screen (is it just me??) and slow write times to my SD card (again is it just me???), but overall quite pleased with the smaller unit.

K-7 screen is adjustable for brightness, saturation etc so just spend some time with the manual to figure out how.

If you have the lens correction function set it takes about twice as long to write. I don't use that and write times are about equal to my K20 - I haven't checked by stopwatch but I use both cameras together to avoid changing lenses and subjectively they're the same.

Again though, I cannot for the LIFE of me take a half decent image with the FA35. So I grab the 77 and the same thing, after two full days of futsing around is appears the camera is severely back focusing with both lenses, even outdoors.

Have you tested all your lenses against a chart? Or at least against clearly defined things that themselves have very distinct points on which to test focus?

On paper this should not be an issue as I can just adjust the AF bias. Thing is, it’s the sheer inconsistency that drives me ABSOLUTELY AND TOTALLY INSANE. I’ll aim at one object and it’s bang on, the next and it’s FF, the next and it’s back focused …… short distances it FF, long it BF ….. it’s a complete and utter crap shoot to be totally honest.

Make sure there's nothing in the way - I once thought my DA70 was badly FF on some portraits, then realised it was picking stray hairs in front of the face to focus on. The focus points are bigger than shown on the screen so even though the red light shines in one place the real focus point can be different. It's reasonably easy to spot this in the VF if you use just one point but if you go to auto and let the camera choose it can be hard to see just where it thinks it's focusing.

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Demarp Contributing Member • Posts: 851
Re: Four years, three cameras and still fighting AF reliability

Well ! you know what ....sometimes the equipment is a reflection of you. What I am trying to say is if you focus to much on problems well you will probably see only problems ! And usually when this happens welll you will probably never enjoy your pentax equipement anymore ! So maybe switching brand should be an option.

I will be happy to buy your stuff ! Call me when the problem comes again and your about to break something I will probably endup doing a good deal !
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OP Alfisti Veteran Member • Posts: 6,649
Re: Four years, three cameras and still fighting AF reliability

I call BS. I noticed it when shooting my wife in our yard, then tried some small flowers (no wind) ... all were absolute rubbish and way OOF.

Demarp wrote:

Well ! you know what ....sometimes the equipment is a reflection of you. What I am trying to say is if you focus to much on problems well you will probably see only problems ! And usually when this happens welll you will probably never enjoy your pentax equipement anymore ! So maybe switching brand should be an option.

I will be happy to buy your stuff ! Call me when the problem comes again and your about to break something I will probably endup doing a good deal !
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gaddigad Senior Member • Posts: 1,906
Re: Four years, three cameras and still fighting AF reliability

Alfisti wrote:

I worked around it for a time, went on a long holiday in 08 and mostly caught keepers with my 12-24, 18-250 and 77 ltd. I also bought an FA35/2 that was razor sharp.

I just got my hands on a K7, I have a few issues with the thing such as a very washed out LCD screen (is it just me??) and slow write times to my SD card (again is it just me???), but overall quite pleased with the smaller unit.

If you're having oof issues with all lenses I'd return the K7 or send it in for a service. I hope you bought from a reputable source, so just use your warranty.

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moving_comfort
moving_comfort Veteran Member • Posts: 8,242
not just you

For what it's worth, you're not alone. I actually had very good experiences with my FA 35, but my 77ltd really starts to hunt in any type of dim light, and gets pretty inconsistent in tungsten frequency. It can be very frustrating, especially when you really wanted a shot that 'lasted' one or two seconds.

I still think the 77 is probably the best overall lens I've ever owned, and because of that I'm happy to live with it's AF faults in combo with my K20D. I strongly suspect that the k-7 successor will make it a relatively snappy performer, though.

My D90 or D700 + 85 1.8D almost never misses, in almost any light, which is why those combos get the call in dim light more often these days. Pity the 85 1.8 can't quite match the 77 in IQ.

Anyway, I have hope that af-lock will not always be this way. When that day comes, very little out there will surpass a Pentax body and the FA Limiteds.

From the 77 in better light:

.

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Voff Veteran Member • Posts: 3,429
Re: Four years, three cameras and still fighting AF reliability

Alfisti wrote:

Here's the thing with sample pics, you'll get all the apologists saying "oh well you need to use a tripod and do this and do that". Well no, when i do that and correct the bias under those conditions I go out and shoot and it's inconsistant, inconsistant, inconsistant. I just cannot trust it at all.

My cameras works like machines. Extremely consistent.

Pentax_Prime
Pentax_Prime Senior Member • Posts: 2,505
Two Words: User Error [nt]

Alfisti wrote:

Four years ago I bought a K100D, kit lenses and an FA50/1.4, I was a happy chappy and new to the DSLR world as many of us were at the time. To cut a long story short, it took me three to six infuriating months to figure out that under incandescent light the cameras AF system goes a little bonkers and despite just dropping $1500 on the set up, I could not trust the AF indoors under said lighting.

I worked around it for a time, went on a long holiday in 08 and mostly caught keepers with my 12-24, 18-250 and 77 ltd. I also bought an FA35/2 that was razor sharp.

Decided to upgrade to a 20D, amongst other reasons for the ability to set AF bias for individual lenses … excellent I thought. I was never really happy with the lack of consistency using the 77 and the 35, well I never once took a decent image with the 35.

I just got my hands on a K7, I have a few issues with the thing such as a very washed out LCD screen (is it just me??) and slow write times to my SD card (again is it just me???), but overall quite pleased with the smaller unit.

Again though, I cannot for the LIFE of me take a half decent image with the FA35. So I grab the 77 and the same thing, after two full days of futsing around is appears the camera is severely back focusing with both lenses, even outdoors.

On paper this should not be an issue as I can just adjust the AF bias. Thing is, it’s the sheer inconsistency that drives me ABSOLUTELY AND TOTALLY INSANE. I’ll aim at one object and it’s bang on, the next and it’s FF, the next and it’s back focused …… short distances it FF, long it BF ….. it’s a complete and utter crap shoot to be totally honest.

I am in the process of determining if it’s just FA lenses but my DA lenses are slow so it’s hard to tell.

Not really sure why I wrote this diatribe, I mean pentax really suit me with the smaller form factor and nice to hold FA primes but dear me, I can only take so much of this. The 77 retails for some $1k and I cannot rely on the camera to nail focus at all.

Four years later and still disappointed.

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