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Do I have back focussing or soft lens????

PostPosted: Fri May 20, 2005 3:50 pm
by georgie
I apologise if this is the wrong place to place this question, but I have noticed that some of my photos are coming out of focus. It got me thinking if I had a camera that had back focus issues. I found a test on the web at http://md.co.za/d70/ and performed the test.

Here is a typical result of mine

The left had side looks fine but the right side seem out of focus. Is this from back focusing, soft lens or just poorly done test?

It was taken with the kit lens.

Many thanks

Image

PostPosted: Fri May 20, 2005 3:57 pm
by Glen
Georgie, hard to say from that but one point is that you are not straight on to the test, you were closer to the right side. Also did you use a tripod and remote? Just thinking if the you didn't align yourself perfectly with the chart you may have also forgot the tripod plus remote.

PostPosted: Fri May 20, 2005 4:02 pm
by georgie
Glen wrote:Georgie, hard to say from that but one point is that you are not straight on to the test, you were closer to the right side. Also did you use a tripod and remote? Just thinking if the you didn't align yourself perfectly with the chart you may have also forgot the tripod plus remote.

This was my exact thoughts thining about it now

Used a tripod and connected to PC and used PC via NC to fire camera - I tried to get it straight but felt I was closer to the right than let

Tripod is not a very good one. It is a lightweight Sony one I got with a handycam a few years back and I think it rotated on the catch to attach it into the camera - tried hard to keep it straight but could still have rotated thus making it inaccurate

PostPosted: Fri May 20, 2005 4:25 pm
by Glen
Seems like you did everything right except being straight on. I used the same test so if I still have it will post so you can see the difference. I think the tripod should be adequate for the test.

PostPosted: Fri May 20, 2005 4:29 pm
by sirhc55
Back or front focus issues would be indicated by - back or front and not side to side. :wink:

PostPosted: Fri May 20, 2005 7:41 pm
by Alex
There is also a simpler battery test whereby you place 3-4 AA batteries in succession one slightly behind the other and focus only on one of them then see the result. The test was posted some time ago on dp forum.

Alex