Focus, equipment, or paranoia?

Started 6 months ago | Discussions thread
eFilm Senior Member • Posts: 1,460
Re: Focus, equipment, or paranoia?

I believe it's a typical case of four separate issues in varying quotients. One of them being yourself, but based on the sample photos there are more than one issue involved.

The first issue is that at least some of those have been shot with fully open lens, which is not the ideal solution. Many lenses benefit from stopping down a bit, and even one stop down will improve the overall sharpness of the image.

The second issue would appear to be slight motion blur, possibly caused by a flimsy (relatively speaking) tripod, or possibly your own action during the shutter being released. Sometimes even wind can make a big long lens wiggle ever so slightly, or your moving about on your feet, nudging the camera when touching it, etc. if/when the tripod and the head aren't a perfect match for the camera and the lens in use. Sometimes it could be a loose quick release plate or something like that. The more megapixels your camera has, the more visible the results of those will be.

The third issue would appear to be the typical SLR back/front focus issue. When you're focusing the shot, either with any sort of AF or manually, your optical viewfinder and the AF sensor would tell you that the focus is spot on, but right on the sensor level it's ever so slightly off, anyway, because neither your eye nor the focus sensor are using the sensor (plane) itself for focusing. Some dSLRs may have on-sensor focus pixels as well these days, or you could use contrast based live view to focus, but that's beside the point here. Again, the more megapixels, the more likely even the slightest errors become visible.

The fourth issue would be the one common denominator behind all of the above, which is yourself. Which is, whatever you're doing during taking those shots.

How to fix those issues, well, the first one is easy, try to stop down whenever possible. The second one will be a bit trickier. Some of it you can fix by being more careful about all sorts of vibrations and movement. Consider experimenting with remote triggers and/or self timers, too, just to see if it works. The other part may be harder without investing in gear. Provided that the support gear is not a good match with the camera gear.

The third one is hard to fix without a major gear change, but you can try minimising it by calibrating the focus once in a while with a focus pyramid, or have it done by a camera service.
The fourth issue is probably going to get fixed automatically as soon as you take care of the first two.

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