Repost of k10D/Sigma 50-500 Shots

[brad_n]

Your comments struck a note with me. I have experienced big CA problems with

the Sigma, though they are most noticeable shooting up into the sky. #2 I've

been using Silky Pics for my Raw conversion and I cannot get the Fringe

adjustments to work #3 I typically use Neat Image for noise removal and

although I keep using a lighter touch I have become suspicious that it does

more harm than good.

 

So I redid the photos from before using PS RAW and not using Neat Image.

 

The Warbler is the same pic as before with the reprocessed version.

 

First upon review of the Red Bellied Woodpecker, I agree that its backfocused,

too far to repair, so I did another photo from the series.

 

I'd appreciate your comments. Any improvement?

 

<img src="http://www.smile-123.com/photos/273902882_XzmcD-L.jpg" /> Original

Warbler

 

<img src="http://www.smile-123.com/photos/274277152_XLzJY-L.jpg" /> Reprocessed

Warbler

 

<img src="http://www.smile-123.com/photos/273820462_DVQzC-L.jpg" /> Original

Woodpecker

 

<img src="http://www.smile-123.com/photos/274277277_Wyypj-L.jpg" />

New/Reprocessed Woodpecker

[azemerov]

Brad,<br>

reprocessed Warbler has better colors, but anyway if your picture is out of focus or too soft you can not fix it in PS. Even if you use sharpen tool it doesn't give you details missing in original image :(<br>

Manual focus is not a problem if camera is adjusted correctly. If you rely on AF confirmation and get constant backfocus (or frontfocus) you probably have a problem with AF adjustment. If you rely on focusing screen and have same problem, screen is not adjusted. In 1st case goto <a href="http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=22023704&page=1">"self focus adjust for dl,ds,ds2,k100d" thread</a>. In 2nd case you can play with thickness of bronze rim laying between focusing screen and frame holding it. In any case don't rush to fix problem before you absolutely convinced you really have it - AF check is not absolutely consistent, neither human eye. Also you can check <a href="http://focustestchart.com/chart.html">focus test chart</a>, but again - don't make fast conclusions, repeat test several times.<br>

Also there is known problem when different lenses give different AF focus results on the same body. There are lot of speculations, but for me the reason it is more likely in combination of AF precision/adjustment problem plus errors in lens AF feedback. Check <a href="http://www.bdimitrov.de/kmp/technology/AF/index.html">SAFOX description</a> for details.<br>

Sorry if I went too far from your original question,<br>

Alex

[gary_merideth]

Brad,

If you want to see some examples of high quality, google Doug Herr and his work will give

the quality goal I believe you are interested in.

g.

[garry_young1]

Photo one is definitely back focused, and as you say it is manually focussed, I think that the lens is the innocent party there ;-). I guess that the other shots may also be suffering from a similar issue. In the first one, the branch is crisp behind the bird, and at f8 it looks great. The third shot in your previous thread looks really good except for obstacles. I would persevere Brad.

 

I have a 500mm Tamron Mirror lens, and the manual focus is really challenging. The advantage you have with the bigma is in the zoom, and the non-fixed aperture, and the lack of donut bokeh, etc., etc. Practice and practice and shoot hundreds of shots for the handful of keepers. (Preaching to myself as much as to anyone else here!)

[brad_n]

Even though these were manually focused, I did the AF test and my camera passed fine. I still have suspicions about the Sigma 50-500 because of the five lenses that I own, it gives me the most problem focusing. That can partially be explained by low light conditions when it tends to hunt for a focus. But, I have other issues with it like manually focusing these above pictures.

 

Perhaps it needs to go in for a CLA.