Autofocus problems (even with focus lock)

[jacsul]

Hello all,
Has anyone come across this problem with their camera. I have a kodak z1012is, got it less than a year ago as a gift. Great starter camera. Recently I'm having problems with the auto focus, at times the images captured are soft or even blurry. The sensor gives me a green - go ahead to take the picture, the image even looks sharp on the LCD screen, but when I transfer the images onto my computer I can see the problems. By removing the battery and or resetting to default setting the problem corrects itself for a short time... I've searched posts, blogs forums and found nothing.
Any ideas before I ship it to kodak to see if it is a defect?

Jack

[Dave Humphries]

Hi Jack,

I did a two minute google and couldn't see anything about z1012is focus problems or errors, either.

I scanned (not fully read) the specs for the model and have come up with the following ideas for you to think about or try;
I'll start with the obvious, don't be offended, but I am assuming we're ruling out camera shake, e.g. due to shutter speed and focal length combinations on the blurry shots?
Has the AF been set to use a single off-center focus point, rather than center or wide area?
Is the IS working properly?
Is the IS being used inappropriately; e.g. when on a tripod or for panning shots?
If using any of the scene modes, is it possible the camera is trying to second guess focus or IS modes somehow? e.g. "Portrait" or "Close up" may prevent infinity focus
Is it slipping into a low res capture mode?
Can the zoom slip accidentally into Macro mode?
Have you looked at/compared the EXIF data for any clues between a good and a bad shots?

Some of the above are no doubt going to be completely irrelevant and can quickly be dismissed.
The only other thing I'd say is don't let the warranty run out (if 12 months) while you investigate.

2 or 3 large, but non-post-processed examples might help us narrow things down.

Hope that helps,

[shreds]

Does the camera have a master reset or factory reset in its menu? I would try this first then ship it to Kodak, especially as you seem to be able to temporarily correct the problem.

Beyond its warranty period it might cost you more than the camera is worth to have it investigated and corrected, so I would act fast.

[jacsul]

Thanks for the reply's,
Kodak has given me an authorization # to have the camera checked under warranty, I'm good so long as it wasn't dropped or gotten wet.
The first 2 photos were taken on the same day, full auto (P&S) I don't recall if I used center focus of multi-zone.





These were taken today in manual using selectable focus.





"Have you looked at/compared the EXIF data for any clues between a good and a bad shots?" I'm not sure how to do this...

Your thoughts, thanks in advance.
John

[Dave Humphries]

Hi Jack,

I have had a look at the EXIF data, there are many ways to do this, most PP or even picture viewing programs on your computer will have an option to review the file or picture information or properties.
I saved all the pictures to my HDD, then I looked using Windows Vista; right clicking the filename in the folder view, selecting the 'Properties' option (down the bottom), the when that opens a pop up window, click for the 'Details' tab and it shows you lots pf stuff about what the camera did.

The only shot that's really unexpectedly bad is the first.
The second, thrid and fourth are OK because of flash, the last two are, I would say, acceptable for the camera and lens you have, this isn't a DSLR and we mustn't expect too much, especially as the last one is significantly digitally zoomed in addition to being at nearly 400mm equivalent focal length.

Convention of EXIF data below = aperture, shutter speed, focal length real/35mm equiv, ISO speed

What I found was;
#1; a natural light shot of two guys leaning on something, it's blurry!
EXIF = f3.5, 1/40, FL 40mm/254mm, ISO400
Camera shake (even with IS) is almost certainly the problem here, for 35mm focal length, non IS would suggest a shutter speed of no less than 1/250 with good technique, add 3 stops for IS = 1/30 BUT there is also a limited depth of field and maybe the IS couldn't cope or wasn't even switched on (EXIF doesn't say). It is just possible it mis-focused closer than it should.

#2; flash shot of a happy couple, sharp
EXIF = f2.8, 1/30, 8mm/41mm, ISO200
This is sharp simply because it is clearly a flash shot (although oddly the EXIF doesn't say so)

#3; ruler, manual focus, flash I suspect
EXIF = f5.6, 1/60, 70mm/396mm, ISO200
Again, I suspect sharp because of flash, focus around the 18cm in centre of pic

#4; ruler, auto focus, flash I suspect
EXIF = f4.8, 1/30, 70mm/396mm, ISO400
Again, I suspect it is sharp because of flash, focus around the 28cm not in centre of pic, note also slightly wider aperture and reduced depth of field, I suspect it focused on the knot on front edge of wood just at bottom of screen

#5; blue light, close focus
EXIF = f8, 1/250, 70mm/435mm, ISO200
This focal length is beyond the optical limit of 396mm, so you have wandered into digital zooming
It's not too bad, but again the rule would be 1/500 for this focal length, was IS on? Probably

#6; bus, distant focus
EXIF = f4.8, 1/400, 70mm/693mm, ISO200
This focal length is WAY beyond the optical limit of 396mm, so you are well into digital zooming
It's not too bad, but again the rule would be 1/700 for this focal length, was IS on, probably or it would be much worse. You cannot expect blue light to also be in focus due to distance and the depth of field is less (much wider aperture)

On balance, you have nothing to lose from getting it checked over, there still could be a problem, it might be AF, or it might be the IS.

Apologies if you know this already:
You might improve your success rate with better handholding technique for non-flash shots.
1) Very gently squeeze the shutter button, don't stab it
2) Especially when zoomed in, keep your elbows tucked into your sides, hold camera with both hands, if possible lean yourself, or better still rest the camera against something solid like a pillar or door frame indoors, or fence or gatepost outdoors.
3) Don't move toward or away from the subject once you have half depressed the shutter button, as that locks the AF.

If I have used any terms you are not familiar with, or said anything you don't understand, just ask. It's easy to drop into the "lingo".

Hope that helps,

[jacsul]

Hmm... human error... plausible. I have 2 weeks to send in the camera under the current authorization #.

This weekend the local Airport is having a "Winter Festival" complete with antique tractors, vehicles, bi-planes, and gliders seems like a good place to test.

Thanks for the info on how to read the image data, this should be very helpful.
Image stabilization mode was always set to continuous, maybe something not to be taken for granted.

Again, thanks for the help.
Will re post
Jack

[Dave Humphries]

Jack,

"Plausible" is as strong as I'd put it, there could be something wrong. I also hope I didn't come across too strongly 'pointing the finger', if so, sorry about that. These things always look worse when read again the morning after and I think OMG did I say that?

Regarding digital zoom:
When you zoom in at the telephoto end, do you hit a stop, then find you can go in further? (possibly with a different color scale) If so, that is the changeover from optical to digital zoom. At least, that's how it works on a Nikon point and shoot I used before my current camera. I hardly ever went into the digital zoom, you can always do that in PP (it is exactly the same thing, throwing away pixels). The added benefit of doing it in PP is being able to recompose for better framing after the event, whereas if you digital zoom and get it wrong, i.e. go too tight and clip something off, that's it, game over.

I can't advise on IS, as I don't have it but that has made me quite good at steadying the camera for handheld shots. The other option is to up the ISO another stop and deal with the extra noise in PP.

Good luck with the weekend shoot,

[atvinnys]

Dave,

on a side note, could you explain to me why the 35mm equivalent is so huge? (factor of 6 or so..)
is that just related to sensor sizes? (in that case, I am somewhat amazed (not quite the right term) bc I thought most were closer to 1.6....)

Vincent

[Dave Humphries]

Hi Vincent,

Yes it is entirely sensor size, mine is a crop factor of 4.7 or so, but the Z1012 has a smaller one still and the crop factor is 5.6. (396/70, which is the Kodak published equivalent divided by the real focal length, both are in the EXIF data too).

To see this more graphically, this chart in Wikipedia is handy, APS-C is left hand on third row, my sensor is directly beneath it (bottom, left) and the nearest to the Kodak is bottom right.

Cheers,

[atvinnys]

Damn, looking right at the sensor sizes on that wiki page got me shivering some...
1/2" sure is tiny...
even then, overall quality is pretty darn good....

Thanks for the link.

Vincent

[Colin Southern]

Damn, looking right at the sensor sizes on that wiki page got me shivering some...

If you want REALLY scary - look at one for a Canon 1Ds3 - think $7000 NZ Dollars to replace - and then send the camera off to Canon for repair, not knowing if you've damaged it or not! (Been there / done that a few months ago!)

[jacsul]

Hey Dave,
No offense taken, I've been I construction for over 25 years. If I've learned anything from this industry it's anything new has a learning curve. This is the first Digital camera I've owned and the last time I shot 35mm has been some time, so I welcome any advice or C&C.

Jack

[jacsul]

Ok, after carefully evaluating my technique I must conclude human error. These images were taken in manual or program mode, IS was turned off and battery was fully charged.
The only editing I used was to enhance color a bit and crop.
Who says you can't teach an old dog the basics...

Dave, again, thank you for your insight.

Jack

[Dave Humphries]

Thanks Jack,

They look good.

Although I would recommend the IS for all but tripod or panning shots, especially for the lower shutter speeds like the 1/30s in the hanger.

On that hanger shot by the way; it looks like the camera has focused on the lower foreground wing or red prop tip, rather than the main subject. probably because it saw more contrast there and is set to wide area focus.
I might suggest using center spot focus, then for each picture, get the most contrasty bit of the subject dead centre, half depress to focus, then re-compose and shoot.

Cheers,

[shreds]

Agree there, centre spot to get the focus right in certain situations, then focus lock it if you can, before recomposing; makes all the difference.

[Roxy]

Ok, after carefully evaluating my technique I must conclude human error. These images were taken in manual or program mode, IS was turned off and battery was fully charged.
The only editing I used was to enhance color a bit and crop.
Who says you can't teach an old dog the basics...

This T-bird looks like a real family favourite!? Puts me in mind of Clint Eastwood's Gran Torino... did you see the movie?

BTW, A good collection of images with your focus practice, Jack

roxy

[jacsul]

Thanks Roxy.