Originally posted by Rusty Rat Than you Marc, that makes sense. All of the lenses I was using were 2.8s, however, when I ran some further tests after my original batch, I noticed enough randomness in the results to tell me something else was going on. I had initially compared shots taken with an SMC-A 28mm f2.8 to other shots taken with DA* f2.8 lenses (most in the f5.6 - f8 sweet spot of the lens). The 28 looked so bad that I thought I had a skunky lens. It was only when I used it on a tripod with flash did the results match what I had expected. A couple of my other SMC lenses didn't exactly "glow" when hand held. Since the image stabilization uses a manual entry of the focal length with MF lenses, that tells me extra software is involved in the process. As an IT guy, it's my first instinct to suspect software (I work with Microsoft products, enuff said).
My ground glass experience ranges from 35mm to 4X5 so I'm quite confident I know how to focus a lens. However, if the focusing screen doesn't return a result that I expect, then all bets are off.
Options for replacement screens?
I have a jinfinance split screen in my K10D which works very well, although some others I believe had had to put shim's to make focus adjustment.
The "gold standard" for split screens is Katzeye, but they are over $100 as opposed to $30. As I was unsure whether I wanted to use a split image finder, I went for the lowest cost option as an experiment and have been happy with it. Note however, being a split image, it will darken on one side or the other (function of viewing angle on the finder) and also interfere with spot metering.
In going back through your posts, I have some questions with respect to focusing.
- What were you using as indication of focus, the red spot or the green hexagon. Many people confuse the red spot (which shows the focus detector that is active) as indication of being in focus, it is not, the green hexagon indicates focus.
- have you tried manual focus with the DA lenses? if you have a DA lens at F2.8 it shoud be just as hard as the KA lenses at F2.8 and the same focal length,
- an observation about focal length, I have found that good focus on wide angle lenses is difficult at best because the depth of field is so good, you can easily make mistakes. In this respect the split image is a much bigger help with accurace focus.
- in this response, and I may have misinterpreted previous posts yoou state with tripod and flash, and the results are sharp like you thought they should be. I had not understood that you had used both tripod and flash together, I thought it was an either / or situation, but if you need flash to have a clean sharp image, to me that suggests the culprit is still camera shake, or shutter speed and subject motion blurr because the duration of the flash is in the 1-2/1000 range and will freexe any image irrespective of shutter speed
As for "extra software" with manual aperture lenses, that is not totally true. In fact there is less processing involved than with a zoom lens because with a manual aperture lens, you do enter the focal length, but once entered, it is absolutely fixed, with a zoom it must be updated at what ever refresh rate is in the camera's processor. Aside from how the camera aquires focal length, once the camera has focal length the calculation is the same for both types of lens, so I do not believe shake reduction would be introducing the error with your manual lenses.
Please note I am not looking to blame the user over camera only trying to identify the cause.
Last edited by Lowell Goudge; 01-13-2010 at 04:25 PM.