Autofocus problems

[danclem]

Hi Chuck:

When our Seattle are group makes the annual Monterey pilgrimage for diving and Backscatter fix, maybe we can get together so I can see how you are shooting. I have had really spotty luck in temperate areas. Always up for learning something new!

Dan

 

[Brewski]

What housing/port are you using?

Its the MDX300 with the compact macro port base and compact macro port S.

My last dive with this combo I added a focus light, and manual focus gear. The lens did focus better, only losing itself a couple of times, when it would I could use the manual focus to get it close and then the auto would lock in.

A friend thought that it may be a camera battery issue as his would hunt when his battery was low, but I'm certain the battery wasn't low.

I do set the camera to single point of focus, and the servo to single rather than continuous.

 

[treb]

Brewski,

I have had the same problem with the same set up you have. Most of the time it works fine in continuous-servo AF mode with either single-point AF or dynamic-area AF. I don't use a focus light other than at night. As you have found out, when it does have problems locking focus it can be encourged into the correct focus range with manual focus after which it wil quickly locks correctly.

I have noticed the same problem occasionally above water, so I don't think it's just associated with UW. It seems to occur when the subject is way out of focus and lacks contrast.

In spite of this little niggle it's a great lens.

Cheers
Treb

 

[Mariozi]

Weird, I have the same exact setup...

 

[Brewski]

Treb, I'm glad to hear it isn't just me. I wonder if there is a glitch with our lenses that doesn't affect the rest.
I sometimes think the lens may be trying to focus on the port glass since it hunts its way close.
Honestly at this time I can't say the focus light has improved matters yet, but I've only had one chance to test it before needing to leave for work, so perhaps in a week I can get some more practice with it.

 

[treb]

Brewski,

It could be a glitch we have in common. I don't think it would be the port glass as the glass is a lot closer than the mimimum focus distance of 8 in. Also, as I said in my last posting, I have had it happen above water which I had put down to lack of contrast in the subject.

Interestingly after the first couple of times it happened, which was on land, I did a quick internet search to see if anyone else had had it happen and I did find a few reports. I just did a quick check again and can't find anything this time.

I'm a bit reluctant to send it off for testing in case I am without a macro lens for a period time. It dosen't happen regularly enough to really worry me and a little encouragement with the manual focus soon gets it sorted when it does happen. I have a few more extended dive trips planned before the end of the year.

I maybe worth posting a note to Nikon to see if there is a known problem.

Cheers

 

[Chuck Tribolet]

Hi Chuck:

When our Seattle are group makes the annual Monterey pilgrimage for diving and Backscatter fix, maybe we can get together so I can see how you are shooting. I have had really spotty luck in temperate areas. Always up for learning something new!

Dan

DanClem: Let me know when you are coming.

My key advice for Monterey is to get as close as possible, and tip the strobes up as
far as possible and still light the subject. The strobe positioning is to minimize
backscatter.

All: It will be interesting to see if Adm. Linda has the same problem. She just got the
60 mm AF-S for her D40 last week (birthday present from me).

Try to get the focus light out over the subject so it's a bit cross-lit. That will
increase the contrast and make the autofocus work better. This was absolutely
necessary to get autofocus to work with the doubler on my RS (There's a large body
of belief that the RS WILL NOT autofocus with the doubler). Ultralight has two
widgets for attaching the Ike MiniC holder to the camera -- get the long one. And
you don't need the gigabuck Hartenbergers and such -- the Ike MiniC works JUST FINE
for $25.

 

[Chuck Tribolet]

Adm. Linda dove the 60 mm today. It's definitely more autofocus friendly
than the 105 mm.

 

[danclem]

Marcelo:

Just returned from two weeks of diving in Oman out of Khasab. Fantastic spot, great photo opportunities! Rita Bento was the marine biologist on board, and she mentioned you were her fellow Portugese speaker in UAE. Small world! Hope to meet you next year when we return so we can compare Nikon/Subal macro focus issues.

Cheers,

Dan

 

[mintaka]

I have the same setup and occasionally have the same issue with the 60mm lens. I frequently have the issue with a 105 which improves a bit with a focus light. I just returned from 10 days of shooting in the Banda Sea, Indonesia and had several frustrating encounters with the 105mm searching for focus.