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.