Sony 90mm Macro and +6 diopter

I have a Meikon a7RII housing with a port for the Sony 90 mm f2.8 macro lens. The port has a 67 mm threaded front for attachment of filters and diopter lenses.  I decided to record the effect of the macro lens with Fantasea +6 diopter lens for both full frame and apsc formats.  6d indicates the presence of the +6 diopter lens.  MFD refers to minimum focal distance measured from the front of the port or from the front of the diopter lens to the target.

The target was an inch ruler with flat front and scale rulings on a slightly backward sloping flat.

No cropping, images shown as recorded.

I found auto-focus in all cases to be relatively fast, sufficient for targets I've seen, but not as fast as nearly instantaneous focus with normal lenses.

Macro lens alone. Focus on bottom flat.

Macro lens with +6 diopter.  Top of sloped rulings out of focus.

90 mm macro, APSC format

90 mm macro with +6 diopter, APSC format.  Focus at center of frame, at slightly sloped back top flat.  Other areas, plus/minus fraction of 1 mm range, out of focus.

Thank you, this is helpful - I'm actually looking for a diopter to augment my A6300 + 90mm setup for a prospective trip to Anilao. +6 doesn't seem to give that much magnification though - frame width goes down from ~23mm to ~16mm, so it should be possible to frame a ~1cm subject, but not the truly tiny stuff that Anilao is famous for. Trying to decide between Weefine WFL03 (+12, $199), WFL05 (+13, $359), and Nauticam SMC-1 ($480).

I was surprised at how fast the focus was with the +6  diopter for both full frame and APSC.  In those cases, the depth of field was maybe 1-2 mm.  Nonetheless, focus was repeatable - impressive.

I don't know what the size of the usual super-macro subject is, but I'm now confident that with the measured minimum focus distances and speed of focus, good shots could be reliably made.

Barmaglot_07 wrote:

Thank you, this is helpful - I'm actually looking for a diopter to augment my A6300 + 90mm setup for a prospective trip to Anilao. +6 doesn't seem to give that much magnification though - frame width goes down from ~23mm to ~16mm, so it should be possible to frame a ~1cm subject, but not the truly tiny stuff that Anilao is famous for. Trying to decide between Weefine WFL03 (+12, $199), WFL05 (+13, $359), and Nauticam SMC-1 ($480).

Have you considered the Subsee +10 diopter lens ($225)? Reports of image quality at Bluewater Photo are good. Calculator shows 2x magnification over 90 mm macro lens alone, and it covers a full frame sensor (and APSC) which could be problematic with the Weefine WFL03.

https://reefnet.ca/products/subsee/

I've seen reports of focusing problems specifically with Sony 90mm and Subsee +10.

Ended up getting Weefine WFL05S - focusing and magnification seem okay in a tub test; will know more when I take it to the Philippines in a month.

I find that holding the camera absolutely still while it focuses is the key. A bit of movement from finning, current, surge, whatever, and it will just keep hunting, but if you hold it still, it's okay. Doubly so with a diopter - I'm currently on a liveaboard, practicing shooting it with a +13 diopter (Weefine WFL-05S), and while it's bloody difficult to lock focus with it, it does work. Manual focus is not available with my housing.