OLY mft Wide/Tele Lens Choice

[Storker]

As I understand it, a low strength diopter helps correct on corners but still has acceptable if not perfect infinity focus.

No, you will get "infinity" focus even with the diopter. Inside the dome and under water, your lens don't have to focus to infinity to focus at infinity. As I said, the dome projects a virtual image. The virtual image is much closer than the subject is, so to focus on a subject at "infinity", the lens focuses much closer. Even with a +2 diopter, your lens' infinity is closer than the dome's virtual image.

 

[Warmwater Wank]

Got it. I appreciate the notion of an achromatic diopter but I'm not seeing Canon's .6 achromatic at B&H etc. and for some reason it sticks that in a previous thread the suggestion was to go with a low strength diopter. Any thoughts on diopter strength? // ww

 

[Storker]

Any thoughts on diopter strength?

I'm happy with a +2: Canon 52mm 500D Close-up Lens 2821A001 B&H Photo Video

 

[Warmwater Wank]

Happy is good! Thanks, seems like a simple enough solution, +2 is sure easier to find so I will stick w/ Canon's acromatic. // ww

 

[Ardy]

WWW: I used the 12-50 in an Olympus housing behind a flat port and was happy with that doing mainly macro and fish shots. Have not used it in the last 2 years as I bought the 60mm macro same as you.

WIde angle is OK at 12mm ie no vignetting but I guess the 9-18 will vignette? is that so? 12-50 example below

 

[Warmwater Wank]

Hey Ardy. Well the 9-18mm in a flat port doesn't vignette but the lateral distortion gets pretty smeary out at the edges.
(The Bunaken sponges shot is uncropped from the 9-18mm, corners don't darken but edges get pretty soft.) Loss of field of view is noticeable (-25%). I ended up with a used Zen WA-100 port from a fellow SB'er (nice deal!) which will help the 9-18mm performance and let me use the 14-42mm a bit more effectively as well. There are better solutions (the 12-40mm Pro) for what I had inquired about but they got beyond my budget. I don't get to dive until next fall but I expect this to help me like the 9-18mm more UW (topside it's a real nice lens). // ww

 

[chris196]

I didn't read every post in chain, but let me give you my experience.
I use a Zen dome, first on an epl2, then an epl7. It's a great option as I can shoot the 9-18, 14-42 and 60mm macro all behind the same port. Extremely versatile. This the one for the 9-18:
Zen Dome Port for Olympus 9-18 Lens

The 9-18 is fine for me, but I'm probably not as much of a pixel peeper as some of the other folks.
And, yes, the 60mm does great behind that same dome. You lose a little magnification, but the 60 is fairly long focal length anyway and it doesn't matter to me.

I see you have the em5 housing with different port type. You can still use the dome I mentioned, but you need an adapter.
As far as cost of 12-40, if you pay attention to olympus outlet, that lens can be had for about $550, but you have to jump when it comes up.

 

[Warmwater Wank]

Thanks Chris. I did pick up that Zen dome (w/ adapter) so am anxious to start using it. While I could use the 60mm with it I'll be switching ports out, since I have a SubSee adapter made for the standard port.

Appropo of very little, I got a 500D acromatic diopter lens for it, based on earlier comments. It has such a large metal ring however that it vignettes at 9mm with the 9-18mm. Seems weird because about half of that metal is totally not needed, not sure why it is so thick.

I am tempted to hacksaw it off--unless I'll be slightly zoomed out anyway to get better corners. Anyone else run into that? I hate to mess it up trying to cut it if I won't be shooting at 9mm anyway due to edge distortion. // ww

 

[Storker]

Anyone else run into that?

Nope, and I regularly use the Canon 500D dry diopter on my 9-18. So that's kinda weird to me.

See my UW pics at Underwater photography Quite a few of them are taken with the 9-18, and all of those from Dec. 2014 onwards are taken with the Canon diopter.

 

[Warmwater Wank]

Storker--Nice shots, thanks for the link. Hmmm, so my diopter has maybe a 15mm thickness, back of threads to front of diopter ring, which is about twice as thick as it needs to be. Seems I have seen remarks about folks usually zooming slightly anyway (like to 10mm or so) to avoid corner problems even with the dome and diopter. If that is not the case, it's gonna be hacksaw time on the front end of that diopter! // ww