disaster

mattox · 2013-04-17T15:17:17+0100

Just came back from a trip to Patagonia and looking over my shots on photoshop. To my shocking surprise all my shots taken with my new 55-300 pentax lens are out of focus. To the naked eye on the lcd screen they seemed fine but back home on the computer they are terrible. I have no idea why! All shots were taken with a low f stop and shutter speeds above 1/200 sec, focus automatic and generally centre point. I am going to test the lens at home at various settings and see if I can get to the bottom of this terrible disaster, but prior to doing so, anyone had any similar problems with this lens? I find that shots taken at 300mm are way more out of focus obvious than say at 200mm, where at 55-150mm some images are almost acceptable if you weren't too fussy.

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mattox mattox

424 posts
17 years

Posted 18/04/2013 - 19:03 Link

i will give this adjustment thing a go then and get back to you all. Thanks for the help everyone

davidstorm davidstorm

4934 posts
15 years
Sheffield,
England

Posted 18/04/2013 - 23:40 Link

Also, try your 55-300 without a UV filter. I think you might be surprised how much difference this makes.

Regards
David

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Nicola's Apartments, Kassiopi, Corfu

Some cameras, some lenses, some bits 'n' bobs

darkskies darkskies

764 posts
15 years
Manchester

Posted 19/04/2013 - 07:34 Link

David is right. The problem you seem to have had was exactly the same for me. I was given a UV filter when I bought the 55-300 and it would not focus. I took off the filter and the lens worked perfectly.

Sorry to hear about your disaster.

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mattox mattox

424 posts
17 years

Posted 19/04/2013 - 11:15 Link

shit....really. the uv filter....mmmm that is an issue then. Will give these suggestions some tests and get back to everyone

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 11:54 Link

so, just taken the camera through some tests: 3 shots at 300mm f5.8, f10, f22 with UV filter, 3 shots 200mm at the same f stops, then 6 shots again without the uv filter. The results very interesting. No noticable difference with or without Uv filter, but all shots taken at f5.8 through all focal lengths noticeably out of focus.

Looking into the fine tuning now and I will see how we go. If required will upload shot that the images can be studied.

Any thoughts. Dodgy lens i think

giofi giofi

904 posts
16 years
Espoo,
Finland

Posted 25/04/2013 - 13:04 Link

Matt, I would consider returning it for repair / replacement.

Giorgio

Pentax Photo Gallery

Mannesty Mannesty

7650 posts
21 years
Totana,
Spain.

Posted 25/04/2013 - 13:11 - Helpful Comment Link

mattox wrote:
...all shots taken at f5.8 through all focal lengths noticeably out of focus.

This is odd when you consider that the AF function is performed with the aperture wide open and once set, the lens elements shouldn't move.

Have you checked the diaphragm to ensure you haven't got a stuck or missing blade?

Peter E Smith - flickr Photostream

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 13:18 Link

http://i859.photobucket.com/albums/ab156/mattox27/IMGP4549.jpg

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 13:20 Link

mattox wrote:
http://i859.photobucket.com/albums/ab156/mattox27/IMGP4549.jpg

this is taken at F5.8

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 13:20 Link

Mannesty wrote:

mattox wrote:
...all shots taken at f5.8 through all focal lengths noticeably out of focus.

All seems in order

gwing gwing

718 posts
14 years
The Chilterns

Posted 25/04/2013 - 13:21 Link

mattox wrote:
so, just taken the camera through some tests: 3 shots at 300mm f5.8, f10, f22 with UV filter, 3 shots 200mm at the same f stops, then 6 shots again without the uv filter. The results very interesting. No noticable difference with or without Uv filter, but all shots taken at f5.8 through all focal lengths noticeably out of focus.

Looking into the fine tuning now and I will see how we go. If required will upload shot that the images can be studied.

Any thoughts. Dodgy lens i think

I'd hazard a guess that the lens is mis-focusing at all apertures but it is just more noticeable at 5.6 due to the shallower depth of focus.

There may be nothing wrong with the lens at all, just the adjustment needed. What it is like *after* adjustment is the test.

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 13:22 Link

had a look into the fine tuning, but cant quite understand one thing. Adjust to the right (+ closer) will make it sharper or more OOF?

mattox mattox

424 posts
17 years

Posted 25/04/2013 - 13:24 Link

this is at F10 OOF is still noticeable

http://i859.photobucket.com/albums/ab156/mattox27/IMGP4550.jpg

giofi giofi

904 posts
16 years
Espoo,
Finland

Posted 25/04/2013 - 13:44 Link

Is this a crop or the whole photo?