Silicon Investor (SI) -- The First Internet Community

STOCKTALK

We've detected that you're using an ad content blocking browser plug-in or feature. Ads provide a critical source of revenue to the continued operation of Silicon Investor. We ask that you disable ad blocking while on Silicon Investor in the best interests of our community. If you are not using an ad blocker but are still receiving this message, make sure your browser's tracking protection is set to the 'standard' level.

Pastimes : Digital Photography -- Ignore unavailable to you. Want to Upgrade?

To: Ausdauer who wrote (7578)	4/25/2004 10:32:02 AM
From: Done, gone.	Respond to of 21646

This means there has to be some contrast or granularity in the subject for the focus to work. The tests I pointed out utilized an optimum focusing target for the camera's AF system. I don't see how the lens itself could be at fault. I'm no expert on the intricacies of precisely how the focusing mechanism works in any given camera. But, the experts seem to think the problem is not all in the body. For example: "the 28-70 mm F2.8 performed the best, clearly showing that this isn't necessarily a camera problem." dpreview.com And so on, google for more...

To: Ausdauer who wrote (7578)	4/25/2004 12:57:39 PM
From: Done, gone.	Read Replies (1) \| Respond to of 21646

I don't see how the lens itself could be at fault. For clarity purposes, here are the entire quotes from DP on this focus issue, regarding the Canon D300 as well as the Nikon D70: Overall [Canon D300] results were as expected, while there is a little variation in the position of DOF (slightly in front or slightly behind) the actual target was always sharp (apart from our 28 - 70 mm F2.8 L which appears to have a problem at 70 mm). dpreview.com The [Nikon D70] results were interesting but not unsurprising, I had noticed the 18-70 mm back focus while taking some test shots and had switched to manual focus for some of them. The 50 mm back focus was more surprising although generally I use this lens at small apertures (F9 or smaller) so this amount of back focus would be soaked up by the depth of field. As I would also expect the 28-70 mm F2.8 performed the best, clearly showing that this isn't a necessarily camera problem. dpreview.com So lenses could be at fault, somehow, across brands. Not clear to me if the problems are the result of bad designs of particular lenses, or if the tests just point out singular bad lenses of particular designs.