Olympus 12-45 info share

[Furnari]

About a year ago, I posted on Wetpixel about my early experience with the Olympus 12-45 and Inon EP01 dome meant for the Oly 8mm:

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Since then, I have used the combination on several dives and it has now become my go-to for pretty much any diving I do, replacing my beloved 12-40 and Inon 170mm dome that I used for many years. That thread devolved into a bit of a pissing contest about whether or not I should be using a port “off label” instead of one dedicated to the lens. As far as I know, there is no dedicated port for the 12-45, but AOI’s port chart calls for the mini dome that’s also intended for the 14-42 and 9-18. Part of being a reasonable adult is a willingness to be proven wrong, and in the interest of bestest for cheapest I recently acquired a used Zen dome also intended for the 14-42 / 9-18: WA-100-EP Pen Dome for Olympus 9-18, 14-42 in PT-EPxx Housings

True, it’s not the AOI port but I can’t imagine the optics are any different. I tested both ports head to head in my AOI OM-1 housing dunked into a tote in my backyard. First up was the Zen, and I was able to repeat the one negative about the lens- close focus distance at 45 is worse than at other focal lengths. That test was with an OM-1 mk I, so just in case the body’s focus characteristics had anything to do with that, I switched to my OM-1 mkII but had the exact same results. I just continued the test from there with the mkII (btw, I used to have the AOI housing for the E-M1mkIII, but sold the combo since I already had the OM-1 mkI and liked the idea of having redundancy as far as cameras if something happened while traveling). Here’s what I experienced:

• The Inon was wider at all focal lengths from a fixed distance (I used the focus light set on the bottom of the tote to keep the distances from the sensor the same- see comparison photos for how I set it up).
• Interestingly, the Inon also has a closer minimum focus distance at 45, so you get slightly more magnification.
• I didn’t try with the Zen, but throughout much of the zoom range you can rest the Inon face down on something with text and still crisply focus on the text- at 12mm the size of the subject was 4-7/8” by 3-1/4. At 24mm, subject size was 2-1/2 by 2-1/8. At 45mm closest focusing distance, it was 4” by about 3-7/8. So, max magnification happens pretty early in the focal range. Works great as a wide (pseudo) macro lens.
• Image quality and corner performance were both better with the Inon, though neither have significant distortion at f5.6. I would happily use the Zen, but prefer the Inon.
• The Inon sticks out about an inch further, and it weighs more. Note that using the Inon dome with this lens requires a 34mm extension ring.
• The AOI focus gear works great, but for some reason it was much harder to turn in the Zen with both camera bodies, which I thought was weird.

Here’s the biggest problem with the Inon: it’s discontinued. If you shoot a housing with native OM-D ports, they make the EP02 dome intended for the 8mm, and it’s still available and uses the same glass. Know how I know this? I scratched the heck out of mine on a dive last winter (don’t ask), and bought an EP02 and had Backscatter swap glass elements with my EP01. It’s worth it because I really do like this combination. After scratching the dome, I researched other 8mm ports, and it turns out the Inon dome is actually slightly larger than AOI, Athena, and Zen domes. Maybe that’s the secret sauce, but I’d love to hear if anyone has tried this with other 8mm domes.

To summarize today’s thesis…the 12-45 is a great mid-range zoom option with a small form factor, saving drag and just about a pound of weight compared to my 12-40 set up. You can find used copies of this lens all day long for $350, and the Zen dome I bought was about $170 shipped from an ebay seller; not too shabby for the level of performance.

 

[sillyrabbit]

Wow! So you really like the 12-45 more than than the 12-40? Great to hear that my Zen port can still work if I get the 12-45mm lens kit with the OM1 mii I am thinking of upgrading to...

I don't know if you remember my previous post about trying to decide on a wide angle lens or a fisheye lens when photography humpbacks... but now that my EPL6's image stabilisation is no longer working (apparently a common thing for the EPL cameras and Olympus will no longer service them), I'm seriously thinking about an upgrade to the OM1 mii...

I won't hijack your thread, but would love to hear your thoughts on a new post I will post and ask you more questions about your experiences and pick your brain (again) for your opinion

 

[d^2b]

Maybe a dumb question, but can I use the 12-45 with the stock PEN port on an EP13? Apparently the 9-18 works there. I understand I could not expect the same image quality wide open (compared to a dome port), I'm just looking for an upgrade path with better overall image quality for my 12-50.

 

[Furnari]

No such thing as a dumb question, especially on this topic since there isn't a lot of info out there. If you're talking the stock flat port, I would say the answer is probably yes, but you would probably get vignetting at the lower end of the range. I used to have the 12-50, and the 12-45 is a significant improvement in image quality.

 

[d^2b]

I looked at this some more today. The 70mm long 12-45 lens might barely fit in the housing with the stock port, but unlike the 12-50 it extends when it zooms, so you'd essentially be stuck at the wide end of the zoom range. I guess there's probably no single port that works acceptably with this lens and with my 30mm macro. The AOI DLP-03 / 04 should work (as you mention above), but I suspect they are too long for the 30mm; that's probably a topic for a different thread though.

 

[Furnari]

One thing I should have mentioned in my original post above was that I use the Inon dome with an AOI 34mm extension ring; I talk about that in the Wetpixel post I linked to, but for clarity (and posterity) I'm pointing that out here: to use the Inon dome with the 12-45, you need an extension ring. In my case, the 24mm extension ring is too short but the 34mm extension ring works great. To answer D's question, I removed the extension ring, reinstalled the dome, and put my 30mm on the OM-1. The photo below is of an AA Eneloop pretty much touching the dome. So, that's one way to skin this cat. This option is not available with the mini-domes like the DLP-03 or the Zen, so while they will likely focus underwater you won't be able to get as close. Domes for the 8mm fisheyes should work better since they're shorter, and would give you the option to shoot the 12-45 with appropriate extension ring(s). Hope this helps; happy to answer more questions.

 

[d^2b]

Does the AOI 12-45 zoom ring for pen housings work in the Olympus PT-EP13 housings? AOI themselves is cagey, saying their zoom rings are only supported in their housings. IIRC they also built the PT-EP13, but so far that is not quite enough to convince me to drop USD70 on a zoom ring. On the other hand, I'm not aware of any alternative zoom rings for the 12-45 in Pen Ports.

EDIT: I realized I have an AOI LG-OM1-1250EZ that works fine in my PT-EP13, so I guess that gives me hope. They both are listed as Φ75.5mm, although I don't really understand if/how that characterizes the whole shape of the gear

 

[js1221]

Does the AOI 12-45 zoom ring for pen housings work in the Olympus PT-EP13 housings? AOI themselves is cagey, saying their zoom rings are only supported in their housings. IIRC they also built the PT-EP13, but so far that is not quite enough to convince me to drop USD70 on a zoom ring. On the other hand, I'm not aware of any alternative zoom rings for the 12-45 in Pen Ports.

EDIT: I realized I have an AOI LG-OM1-1250EZ that works fine in my PT-EP13, so I guess that gives me hope. They both are listed as Φ75.5mm, although I don't really understand if/how that characterizes the whole shape of the gear

I don't have a PT-EP13 to test it out but I do have zoom rings for the 12-45 and the 12-50. The base of the 12-45 ring in just a tiny bit smaller then the 12-50, but the barrel end of the 12-45 is just a tiny bit larger then the 12-50. I've used the 12-45 and 12-50 in the AOI DLP-03, so I would imagine if you would be alright if you're planning on using that port, or the Zen port. That's just my guess though.

 

[Furnari]

I'm pretty sure that the AOI gear should work in an Olympus housing, especially based on what js says above. It should just come down to how well the gears play together. To that point, I dug up a couple of Olympus zoom gears intended for use in their M43 housings- one for the 14-42 and 9-18 and the other for the 7-14. Both meshed nicely with AOI PEN gear for the 12-45, which tells me the gear teeth dimensions are close enough to work.