I just got an Ikelite housing for my D700 and I'm new to shooting a DSLR underwater (not new to either DSLRs or UW, just to putting them both together). My 20-35mm 2.8 doesn't want to focus on anything. it keeps going all the way in to minimum (1.7ft) and I think it's trying to focus on the port. I've tried multiple scenarios, shooting at something very defined far away or very bright, nothing seems to work. On land it will focus on anything, even very subtle differences on a dark subject.
I think it may be either the magnifying affect underwater or that there's a setting I'm overlooking, any help will be appreciated, thanks!
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I just got an Ikelite housing for my D700 and I'm new to shooting a DSLR underwater (not new to either DSLRs or UW, just to putting them both together). My 20-35mm 2.8 doesn't want to focus on anything. it keeps going all the way in to minimum (1.7ft) and I think it's trying to focus on the port. I've tried multiple scenarios, shooting at something very defined far away or very bright, nothing seems to work. On land it will focus on anything, even very subtle differences on a dark subject.
I think it may be either the magnifying affect underwater or that there's a setting I'm overlooking, any help will be appreciated, thanks!
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This lens' closest focusing distance is 20 inches. It may be that the port you're using produces a virtual image that is closer than 20 inches. If so, your lens is simply searching throughout its range for a sharp image which it can never find. If this is the case, the simplest solution would be to add a diopter to the front of the lens. This will allow the lens to focus on a point closer than 20 inches. I hope this helps you.
Randall Benton
This lens' closest focusing distance is 20 inches. It may be that the port you're using produces a virtual image that is closer than 20 inches. If so, your lens is simply searching throughout its range for a sharp image which it can never find. If this is the case, the simplest solution would be to add a diopter to the front of the lens. This will allow the lens to focus on a point closer than 20 inches. I hope this helps you.
Randall Benton
I was thinking that may be the case but I can't seem to find anyone else having the same problem. When an object I'm shooting is 20 inches away it's in focus. Also, if I enable the lens to focus on the virtual image wouldn't that be out of focus for everything in the water?
EDIT:
I'm looking up info about diopters now, still trying to see if this will solve the problem. So the port (dome) is making everything, even far away objects, look like they are closer than 20inches? And with a diopter this will correct that and give me a natural focus range, how do I know which power to get (+1, +2, ect)?
I just got an Ikelite housing for my D700 and I'm new to shooting a DSLR underwater (not new to either DSLRs or UW, just to putting them both together). My 20-35mm 2.8 doesn't want to focus on anything. it keeps going all the way in to minimum (1.7ft) and I think it's trying to focus on the port. I've tried multiple scenarios, shooting at something very defined far away or very bright, nothing seems to work. On land it will focus on anything, even very subtle differences on a dark subject.
I think it may be either the magnifying affect underwater or that there's a setting I'm overlooking, any help will be appreciated, thanks!
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Hi- I checked the ikelite port chart on there web site. It says the folowing. Port are 5503.50 or 5510.16 but both require a +4 diopter or the focus won't work.
*20-35mm D
#5503.50
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#5510.16 †
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(*) Zoom Lenses require addition of a +4 diopter close-up to the lens for full range operation underwater behind a dome port. Check lens measurements as described on the SLR Port Specifications page to confirm these recommendations.
Once you've put on the +4 closeup lens, you will not be able to take photos top side (while camera is in housing) as now your range is shorter than 12 inches.
