EOS 10D autofocus not working.

[grouchyturtle]

I pretty much a newbie with this, so sorry for the long post. I think I figured this out on my own, but just wanted to post here, to be sure.

I'm currently using an EOS 10D with an Ikelite 6871.11 TTL housing and a Sigma 18-125mm F3.5-5.6 DC lens with an Ikelite 5503.30 dome port.

I plan on getting an Ikelite DS-125 and a DS-50, but currently don't have any strobes. Also plan on possibly getting either a Tamron SP AF11-18MM F/4.5-5.6 Di II LD or a Sigma 10-20mm F4-5.6 EX DC lens.

Anyway here is the problem. I can't get my camera to focus while underwater. It's not a problem with available light, because I have somehow managed to get a handfull of shots, on the same dives where I'm having this problem, but most of the time it just won't focus at all. On the surface, while still in the housing I have no problems.

I looked at the Sigma site and noticed that the minimum focusing distance for my lens is 19.7". Ikelite doesn't have my lens listed on their port chart, but I did see this on their port page.

Many zoom lenses require a +4 diopter close-up lens available from camera stores. Wide angle lenses will focus at 12" and do not require the addition of any close-up lens when used in a dome port.

So, I'm guessing I'm having this problem simply because I don't have a diopter on my lens, right?

 

[grouchyturtle]

Gee not one response?

Ok, talked to Ikelite today and they confirmed what I was thinking.

 

[StevenB]

I think you might get more response posting this in the general photo area rather than the Canon Corner. I think it is a general enough question that others without this particular cam/ lens combo might be able to advise. Most likely it is due to lower light level underwater, some lenses have a more difficult time focusing in less than optimal light. Try another lens.

Are you using any filter? If so try removing it. Are you using a center spot focus or multiple spot? Try it with just center spot focus. Are you using any focus light? That might help a lot on closer subjects.

Steve B

 

[padiscubapro]

I pretty much a newbie with this, so sorry for the long post. I think I figured this out on my own, but just wanted to post here, to be sure.

I'm currently using an EOS 10D with an Ikelite 6871.11 TTL housing and a Sigma 18-125mm F3.5-5.6 DC lens with an Ikelite 5503.30 dome port.

I plan on getting an Ikelite DS-125 and a DS-50, but currently don't have any strobes. Also plan on possibly getting either a Tamron SP AF11-18MM F/4.5-5.6 Di II LD or a Sigma 10-20mm F4-5.6 EX DC lens.

Anyway here is the problem. I can't get my camera to focus while underwater. It's not a problem with available light, because I have somehow managed to get a handfull of shots, on the same dives where I'm having this problem, but most of the time it just won't focus at all. On the surface, while still in the housing I have no problems.

I looked at the Sigma site and noticed that the minimum focusing distance for my lens is 19.7". Ikelite doesn't have my lens listed on their port chart, but I did see this on their port page.

So, I'm guessing I'm having this problem simply because I don't have a diopter on my lens, right?

I agree with ikelite.. I suggest you search ebay for a closup kit for whatever thread your lense is..

They usually come with +1, +2, +3, +4 and +10 (macro)
you can then try different aues (different dives of course) to find out what works on your lens. They can also be stacked, say you need a +5, just put a +4 and a +1

I would start with the plus 4, then try one one either side comparing the focus of the 2 at both minimum and maximum zoom.. if they are right changing the subject distance shouldn't create any problems..

 

[grouchyturtle]

I'm going to pick one up and hopefully give it a try at Bainbridge or off NJ next weekend.

Most of the kits I've seen come with only 1, 2 and 4, with the idea that 3 isn't necessary, because you just stack 1 and 2.

From what I understand each whole # magnifies 25%, so a +4 would double the lens?

If that's the case +4 is the one I need. +3 would give me a focusing distance of about 15", +4 would make it about 10".

I think all domes create a virtual image at 12", right?

Guess I'll find out next weekend.

 

[padiscubapro]

I'm going to pick one up and hopefully give it a try at Bainbridge or off NJ next weekend.

Most of the kits I've seen come with only 1, 2 and 4, with the idea that 3 isn't necessary, because you just stack 1 and 2.

From what I understand each whole # magnifies 25%, so a +4 would double the lens?

If that's the case +4 is the one I need. +3 would give me a focusing distance of about 15", +4 would make it about 10".

I think all domes create a virtual image at 12", right?

Guess I'll find out next weekend.

No all domed ports don't put the image at the same spot.. its mainly a function of the diameter of the port and the thickness of the glass(plastic)

Each plus rating adds 1 diopter to the lens.. so if you had a 6 diopter lens and a +4, it wouldbe a +10

this page has some good info (as well as the rest of the site)
http://www.seafriends.org.nz/phgraph/macro.htm

 

[Nocturnal Lights]

Check out our SLX auto focus lights, it'll help you guys take better pictures (especially macros)

http://www.nocturnallights.com/underwater_photography_lights/slx_led_auto_focus_assist_light/

 

[grouchyturtle]

Tried it out this weekend at Dutch. Worked perfectly.