Nikon 5T and 6T with 105 VR Lens + Subal 105VR Port

Has anyone used the Nikon 5T and 6T diopters with the 105VR lens in a Subal 105VR Port? I'm talking about the newer 105VR Subal Port that is longer than the 105VR Port that Subal first came out with. I was talking to Ryan at Reef Photo on the phone the other day and it seems Subal doesn't really provide a good answer to this question. Therefore, I wondered if any of you have had actual experience using the combination of either the 5T or 6T underwater with this lens and port. In a nutshell, I would like to know if there is enough room for the diopters to fit on the end of the lens without scratching the glass on the port.

For the old 105 lens, I had to purchase a step-up ring to use these diopters, but the 105VR lens has the same diameter as the Nikon 5T and 6T diopters so no step-up or step-down ring is required.

Thanks in advance for sharing your thoughts and your experiences.

Ellen

good advice, scratches on the inside of a port are nasty! don't ask me how I know, lol

scott

To see if it will work set up the camera with the lens and 5T or the 6T, put it in the housing without the port on, put something soft over the lens (lens cleaning cloth) and secure with a rubber band. Put the port on, if it touches you will need a short extension for the port.

Thanks, Dan. I will try that.

I see you are just across the river from me. I did not know we had any underwater photography shops in the area. I'll have to check out your website.

Thanks again.

Ellen

I can tell you this, I use a T3 quite a lot when I shoot macro and have a T5 to, but the depth of field is so small with a T5 that it is very very difficult to use.

Nikon made two dual element close-up lenses in the 52mm thread size, suitable for the older 105mm Micro-nikkor. They were approximately the same strength as the T5 and T6 which 62mm thread size and were introduced about the same time as the 70-180 Micro-nikkor zoom.

Dual element diopters act quite differently, in an optical sense, than single element diopters. I once had one of the older dual element Canon CU Lens 240's cut in half with the thought that it would make better over/under pictures with the wide-angle lens I was using it on - Nikon's older 20-35mm zoom. To my surprise, when I went into a pool to check it out, the above water and underwater halves of the image did not match, the angle of view of the underwater part of the image was considerably (25%?) narrower than that of the topside part. The two halves did match with a single element diopter.

My conclusion is that whereas a single element diopter just shifts the focus range of the lens it is on, a dual element close-up lens gets most of its "power" by narrowing the angle of view of the lens. A way to see if this is so with the 105VR and a T5 or T6 would be to focus on a subject (at about about .5x or even 1:1) without the diopter. Then focus on the same subject with the camera in the very same position with the diopter. IF the subject is the same size from the same working distance, then the close-up lens is ONLY shifting the focusing range of the lens. IF the subject size is smaller, then the close-up lens is narrowing the angle of view of the lens, effectively making the lens act like a lens of longer focal length.

This whole test can be done on land in just a few minutes. IF the T5 actually narrows the angle of view of the lens, this might be a contributing factor as to why kriptap feels the depth-of-field is so small when he uses it

Fred

Oops! forgot to say that the 52mm Nikon close-up lenses were called T3 & T4.

Fred

The 52mm diopters were called the 3T and 4T. The 62mm diopters were called the 5T and 6T. The 3T and 5T were +1.5 diopters. The 4T and 6T were +3. In my experience none of them had any special effect on DOF as you would not expect any. DOF narrows as magnification increases, of course. Focus can be harder to achieve at f/2.8 but the end result is the same.

In order to retain image quality when using close-up lenses on AF Micro Nikkors (and possible also the MF 200/4 Micro Nikkor) it is advised to mount them in a reversed position.

A thread reversal ring is then needed. I could not obtain one and solved the problem with two Cokin filter rings glued together. The reason why reversal gives better result is said to be improved spherical aberration.