I started taking a very critical look at my recent work from my Nikon D90. I noticed that in some conditions my shots were a bit "soft", and in a couple of lower light cases they were just plain out of focus.
I reset my cameras focus setting - changing the focus point to locked in the center - reasoning that if that was my main subject (as it would be most of the time) then I would force the sensor to concentrate its focusing powers there.
But - in situations where there was not a lot of depth-of-field support (cloudy, indoor, etc.) the focus was still off a bit. Oh - I don't mean when I reviewed them on the camera screen - those appear to be optimized for showing your work in its best possible way. I mean when viewed on a monitor while post processing.
So - I started researching back focus complaints about my camera. There were a few for sure. many of the later Nikon's allow for micro adjustment of the focus system in camera firmware. Pretty nice, and you can get dead on with each lens you use. The D90 is a bit older, so no firmware adjustments are available, but there is a manual adjustment - but I don't want to stick a tiny Allen wrench anywhere near my sensor or mirror - I'll gladly let an expert do it.
So - I checked my local Big Box camera store - in Austin that's Precision Camera. They charge $29.00 to micro adjust your camera - what a bargain. They took a couple of shots that look fantastic on the camera screen - until you blow them up. Then the back focus issue comes into clear view (bad pun). Here is a shot of their focus board:
This is a crop of the original - centered on the focusing jig. The main focus point for the shot is the zero mark - and focus, I guess, should be crisp at zero and equidistant up and down the line.
When I re-crop to enlarge just the scale we see this:
Clearly this shot shows the image as favored more to the back - the reference point marked 8 is in focus behind the zero mark, but not in the front. In fact - the small 16 at the rear is still sharp and clearly not focused in front.
Apparently front/back focusing issues can be found in many cameras. If you think your shots look too soft you might want to check it out.
BTW - I get the camera back tomorrow, just in time to fly to Portland, OR, to watch my daughter graduate Chiropractic School. I get to ask her "What's up Doc?" with a straight face, now!
Focusing Issues
Focusing Issues
Gene
"It could probably be shown by facts and figures that there is no distinctly American criminal class except Congress."
Mark Twain
"People shouldn't be afraid of their government. Governments should be afraid of their people."
Alan Moore
"It could probably be shown by facts and figures that there is no distinctly American criminal class except Congress."
Mark Twain
"People shouldn't be afraid of their government. Governments should be afraid of their people."
Alan Moore
Re: Focusing Issues
There's also an issue with focus-shift with some lenses - they focus correctly wide open then shift the plane of focus when you stop down. The last generation of Leica Summilux 35mm ASPH was affected, not enough to show on a film camera, but would show up on a digital Leica with a thinner sensor layer than the emulsion of a film. That was the reason for the current floating element version of the Lux 35.
Chris
PS Congratulations on your daughter!
Chris
PS Congratulations on your daughter!
"Je n'ai pas besoin de cette hypothèse."
Pierre-Simon de Laplace
Pierre-Simon de Laplace
Re: Focusing Issues
This thread reminds me that I am way overdue in getting out locally to take some snaps of winter in Ottawa .... cruddy lighting today, so there is no way that's happening. We have our oldest granddaughter this weekend for the season's first sledding runs, so I expect my wife with be Instagram-ming like mad throughout the day .....