Fuji GA645 and close focus

RattyMouse · Aug 31, 2012

I seem to be getting consistently bad focusing when trying to take pictures of my daughter. I am not sure what I can do to improve this. It is very rare to get a nice sharp photo at the distances seen in these images. Inside I am typically shooting at f/4 or f/5.6. Depth of field is not a lot I guess but I would hope that this camera could do better. The camera never indicates that I am exceeding the minimum focus limit. Any ideas what I can try differently? Thanks!

summicron1 · Aug 31, 2012

some children are just naturally fuzzy

-- these don't look bad to me, but in the second her arm looks a tad sharper than her teeth. On the first you can see that the hair on the side of her head is sharp, but her face is not, it is projecting into the soft zone.

With that long a lens on a medium format, at f 4.5 or 5.6 your depth of focus is going to be pretty narrow. Remember that the zone of sharp focus projects behind the point of focus 2/3 of the zone, and only 1/3 is in front of the point of focus.

This is why when you focus you pick a point on the front of her face slightly behind the nose -- her eyes or the bridge of her nose -- then her nose is sharp but more of the rest of her head is also. If you just focus on the outline of her head you are really picking a point somewhere around her ears, which is what the top pic looks like.

This all assumes your rangefinder is not out of alignment.

Thomas Bertilsson · Aug 31, 2012

There is a way to focus your GA645 manually.

I don't know how different the 645 is to the 645i, but here's a link to a manual: Click

I used to own one of the GA645i cameras, and it was a pain in the 'you know what' to focus manually, but it should be doable.

Your other option is to step back a little, so that your depth of field becomes less narrow, and then crop. Or get a manual focus camera.

- Thomas

cramej · Aug 31, 2012

Maybe the camera needs some adjustment. It looks like it back focused by the same amount in both images - just behind the face right along the ears and hair line.

RattyMouse · Aug 31, 2012

summicron1 said:
some children are just naturally fuzzy

-- these don't look bad to me, but in the second her arm looks a tad sharper than her teeth. On the first you can see that the hair on the side of her head is sharp, but her face is not, it is projecting into the soft zone.

With that long a lens on a medium format, at f 4.5 or 5.6 your depth of focus is going to be pretty narrow. Remember that the zone of sharp focus projects behind the point of focus 2/3 of the zone, and only 1/3 is in front of the point of focus.

This is why when you focus you pick a point on the front of her face slightly behind the nose -- her eyes or the bridge of her nose -- then her nose is sharp but more of the rest of her head is also. If you just focus on the outline of her head you are really picking a point somewhere around her ears, which is what the top pic looks like.

This all assumes your rangefinder is not out of alignment.

I always focus on the eyes, so that didnt work for me. The GA645 isnt a true rangefinder so I am not sure what is there to be aligned.

Brian C. Miller · Sep 1, 2012

I have a GA645zi. These cameras have a minimum focus distance of 3ft, so you have to watch that. While your camera may correctly measures the distance between you and the subject, the motor and sensor used to position the lens may put the lens into the wrong position, and so it's something you only see with a close subject.

Try a focus test. Point your camera at a wall, and just press the release to the first detent to activate the autofocus. Note the focus indicator, and keep repeating this until you are at the camera's minimum OK focus. At this distance, in bright sun, make a photograph. After the film is developed, see if the image has good detail.

I noticed in the first image that your daughter's left shoulder seems to have some motion blur. The Fuji autofocus doesn't readjust for a moving target, and she could have moved between the focus phase and the shutter release.

RattyMouse · Sep 2, 2012

Brian C. Miller said:
I have a GA645zi. These cameras have a minimum focus distance of 3ft, so you have to watch that. While your camera may correctly measures the distance between you and the subject, the motor and sensor used to position the lens may put the lens into the wrong position, and so it's something you only see with a close subject.

Try a focus test. Point your camera at a wall, and just press the release to the first detent to activate the autofocus. Note the focus indicator, and keep repeating this until you are at the camera's minimum OK focus. At this distance, in bright sun, make a photograph. After the film is developed, see if the image has good detail.

I noticed in the first image that your daughter's left shoulder seems to have some motion blur. The Fuji autofocus doesn't readjust for a moving target, and she could have moved between the focus phase and the shutter release.

My GA645 focuses down to 0.7 meters, which is significantly closer than 3 feet. I always watch the distance that the camera measures but it is hard to tell if my girl is 0.7 meters or 0.8 meters away. So I have to trust the camera. I will measure out 0.7 meters and do the focus test.

MattKing · Sep 3, 2012

Remember as well that the focus system focusses at a particular point (the autofocus spot). It is not out of the realm of possibility that the indicator in the finder could be out of alignment with the actual point of autofocus.

Fuji GA645 and close focus

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