I recently baptized a coworker of mine into our small but growing parish of analog photographers. He found an old Pentax MX in his dad’s attic, I inexplicably had a minty K-mount 200mm f/4 lens sitting around (I don’t own any Pentax cameras, so why I had that lens is a mystery to me), and long story short, we found ourselves burning some film on a lunch break at one of the nature trail areas near the office.

I was shooting my Olympus OM-G and had my own 200mm lens attached. You know, the one that it actually made sense for me to own because I have an Olympus camera. Out of nowhere, my buddy tells me to come over to where he’s shooting, very quietly and slowly. Matt had noticed a Cooper’s hawk sitting in a tree. But it was sitting on about the lowest branch there, probably 10 feet off the ground. I’ve never been so close to a wild bird of prey. And of all the times for that to happen in my life, I can think of worse ones than “while I’m out shooting nature photos with my longest telephoto lens in my hand.”

I managed to get this shot. And I’m quite happy with this shot.

But something had changed in me that day. I’d had a taste of a potent drug I managed to avoid to this point: wildlife photography. Suddenly, my 200mm felt like a wide angle. I needed lenses that were longer, chunkier, heavier, and more expensive. The Sigma 200-500mm f/2.8 was slightly out of my price range, so I settled on a gently used OM Zuiko 300mm f/4.5. It was really affordable from KEH, and has a reputation for being very sharp, even wide open. Which is good, because I’m not used to lenses where f/4.5 counts as “wide open.” As a bonus, I can shoot this lens on my 5D2 as well, because we all know my Canon body and OM lenses are a match made in heaven. Or, you know, Japan.

I took it out for a spin on my 5D2 and was very impressed with the results.

But my thirst for focal length gains was not to be so easily slaked. In my lust for sheer telephoto excess, in my hubris, I ventured into an elephant graveyard best left to the hyenas. Not just teleconverters (already the analog equivalent of “digital zoom”). No, I’m talking about 3rd-party, no-name brand, 2x teleconverters available from dark corners of eBay for $5. I had taken my perfectly good 300mm f/4.5, and turned it into a probably bad 600mm f/9, and there was no metaphorical Mufasa to swoop in and rescue me, and then give me a stern but fair lecture about my poor decision, and then frolic around in the grass and promise me we’d always be together.

So how bad is it really? As penance for my sins, I have done the testing necessary to find the answer to that question. I didn’t expect much. But it was $5, and the actual Olympus brand ones are expensive. So I figured it was worth a shot.

Here is the matrix of test images, all 100% crops. Everything was taken at 100 ISO, on a sturdy tripod, with mirror lockup and a cable release. In Lightroom, I balanced out exposures, cropped, and gave each frame my best treatment to make it look as sharp and good as possible (since that’s what I would do with a real photo too).

The 300mm without the teleconverter is a great performer at all apertures, corner to corner, with a sweet spot around f/16 or thereabouts, and diffraction only starting to get noticeable at f/32. No reservations using this lens whatsoever.

When you add the 2x teleconverter, it takes an obvious and noticeable hit in quality when looking at 100% crops. In the center of the frame, it isn’t too bad by f/8 and f/11, and is very usable at f/16. In the corners it’s pretty awful until about f/22, but for a wildlife lens that doesn’t really matter.

I think I’ll take it out for some real world use and see if I can come away with any shots that I like, and gauge whether the sharpness hit ruins them or not. But I’ll tentatively say this chunk of glass was worth the $5 I paid for it, at least.