Cheap vs. Expensive Speed Booster / Focal Reducer test... For Science! (Not actually for science.)

This one's for all our Photography Nerd readers. Or, rather, it will be once we get some.



WHY THIS TEST? (A little geekdom here, but not too much.)

I recently found out that Fujifilm (maker of cameras and film stock from Way Back) cameras have, in their firmware, "film emulation" presets. Unlike the silly generic filters that most cameras have in them, the Fuji mimics, as close as you can hope for, the look of Fuji's famously beautiful film stocks, as well as others by Kodak, etc. So, there are film presets like Velvia, Portra, Kodachrome, and many others. Since playing around with vintage lenses is very much a thing of mine, this discovery was one which made my eyebrows do an excited little dance. Fast forward a week or so, and I became the new owner of a used Fujifilm X-T10: a camera from about five years ago, making it positively ancient in digital camera years. As a result, it was pretty damn cheap.

Now, most old lenses are meant for shooting on a 35mm camera. Trouble is, not all current cameras have an image sensor (the digital bit that does the job that film used to do) that's the same size as a 35mm film negative. The Fuji camera I just picked up has a sensor 25% smaller than the image that an old lens projects onto it. So as a result, the outer edges of the image falls off the edge of the camera's sensor and isn't captured. The lens will still work on the camera, but the image will be a little more "zoomed in" than it should be, and also, you lose some brightness, since not all of the light is hitting the image sensor. In general, this whole situation is called "crop factor".

For more detailed explanation, your browser will more or less explode with pedantic photography enthusiast opinions when you search on "camera crop factor". Enjoy

A cropped image isn't ideal, because, with vintage lenses, lots of the interesting stuff you get comes from the edge of the lens. Some lenses have darker edges (vignette), and lots of old lenses, in the out of focus areas, don't just blur the image, they smear or swirl the image in crazy ways (swirly bokeh). Yes, technically, these are flaws. But, in the age when your average smartphone can capture bright, sharp, accurate images with impressive fidelity, the weirdness of old lenses deliver personality and charm. This is where the fascination comes in. So, losing the edges of the lens' image loses part of the fun.

To remedy the problem of  cropped images when adapting old lenses to non-full-frame (or "cropped sensor) cameras, there are things called "speed booster / focal reducers". Any vintage lens is going to need an adapter just to be mounted on the modern camera body, but a speed booster is an adapter that also has in it a corrective lens that focuses the incoming image down to fit better onto the image sensor. This not only has the effect of making the picture look more like it should. It also makes the image brighter, since much less light is being thrown away. On average, a focal reducing adapter like this will add a full stop of extra light to the image.

A company called Metabones basically invented focal reducing lens adapters, and as of this writing, theirs are still unquestionably the best. If you're putting yet another glass element between the lens and your camera, you want it to be as well made as you can afford, so it only helps - and does no harm to -  the resulting image. There are now many MANY cheap knockoff speed boosters, mostly made in China, which cost less than 1/6 of what you'd pay for a Metabones model. Are they all junk? How close can you get to the performance of the original Metabones for a fraction of the money? Good question.

IT'S A WHAT, THEN?

The generic term for these devices is "speed booster / focal reducer / lens adapter". The "speed booster" term comes from the fact that you're getting more light on the sensor and can then use a faster shutter speed. Blah blah blah. Anyway, this generic term is a mouthful, so when someone says "speed booster", they're talking about these devices and don't want to use the whole phrase, maybe because they have to work in the morning.

SHAMEFUL SHOPPING

Shortly after buying the Fuji camera, I went on Ebay and bought a Chinese speed booster. The listing didn't mention the brand at all. So, consider it generic. It cost $70.

After a few days, temptation got the better of me and I bought a Metabones speed booster. It cost $450. Ow. That's much more than I paid for the camera it's meant to work with. But, I've had one for my Olympus camera for years, and I knew their stuff to be built to a very high standard with state of the art glass in it. It's definitely a price that's hard to overlook, but with fifty-ish old lenses that will work better in its company, I found a way to justify the expense.

All of my old lenses are adapted to the ubiquitous Canon FD lens mount. I have Nikons, Canons, Asahis, Mirs, Meyer-Gorlitzes, Helioses... and they all have little adapters on them to convert them to the Canon FD bayonet mount, just because it was so common. So, both of the adapters I bought convert Canon FD to Fuji X mount.

This picture may help make it clear what the speed booster / lens adapter / focal reducer is doing.


From left to right: Early 1970s Asahi-Pentax Super Takumar Lens (with a thin little Canon FD adapter stuck on it), Metabones speed booster adapter thing / camera body.

THE CONTENDERS

Disclaimer: I didn't get these for free. I spent my own hard-earned Big American Bucks on them.

On the left is the Metabones ($450). On the right is the Pixco ($70). Oh, by the way, the previously anonymous Chinese speed booster turns out to be a "Pixco" branded unit. The Ebay seller might want to mention that in their listing. Anything to help it seem less like a fly-by-night Ebay scam.

Interestingly, the lens in the Metabones adapter is a little larger in diameter. Also notice that the Chinese version only has three screws holding it together, while the Metabones has five. This kind of stuff can be found throughout a casual examination of both units. Unsurprisingly, the Metabones weighs a little more than the Pixco.

PEEPING THE PIXELS

The test image I used is a huge framed poster of 8 bit pixel art. It has lots of color and detail, so it seemed like a good choice. If you're looking for laboratory conditions and stuff, you might want to head over to DPReview.com, because you ain't getting that here. Sorry not sorry.

Both sets of test images were taken using the same Super Takumar lens with the aperture wide open at f/1.8. Don't forget that it's a manual lens, which means that both images were focused manually by yours truly, which introduces an unavoidable margin of error.

This image will open at 1600px wide if you click on it.

Blah blah image 1600px click, etc.

For seventy dollars, the Pixco is not bad! Colors are pretty much the same as those produced by the Metabones, and sharpness is roughly equivalent... in the center, at least. To flip between them, try opening each in a new browser tab.

Here's a 2-up shot of the above images...

Click blah 1600 bigger, blah.

Click big etc. etc. etc.

This image (above) is a 100% crop of the center of each image. So, one photo pixel is one image pixel on your screen.

The Pixco is still not bad for seventy bucks. The Metabones has just slightly more contrast. So, maybe the Pixco has just a tiny bit of haze in the glass. Look at the black outlines on the soldiers to see this. But still, that's splitting hairs.

At the edges is where the differences become much more obvious. This is the upper left corner of the image. The Pixco loses a lot of contrast and clarity at the edges. This is where the extra $380 dollars went. Sure, the Metabones is better, but is it 600% better?

CONCLUSION

The Cheapco Pixco does a fine job for $70! (Well, the copy I received, at least). Thankfully, there are obvious differences in the Metabones image, so I don't feel like a sucker for spending the money on it. But a side by side comparison like this is something that I would have liked to see before I spent the money, purely in the interest of making an informed decision.

The Pixco is definitely softer at the edges. But really, is this a deal breaker - especially for someone interested in using the adapter purely with vintage lenses, which generally feature "quirky shenanigans" at the edge of the image anyway? I mean, I don't feel any buyer's remorse about the Metabones, partly because it's a beautifully made bit of gear, and I like that any personality in the resulting images will come from the old lens, and not from a lens adapter engineered down to a price point. But if I was, say, a college student who couldn't justify over four times the price, the Pixco is a more than acceptable option.

One thing to consider, though, is this: With a major company like Metabones, you can pretty much count on consistent quality from one example to the next. When buying  a no-name brand with a name you've never heard of from an anonymous factory, personal experience has shown that every purchase is a roll of the dice. Part of what you're paying for when you buy a known product from a company with a reputation to protect is not just the quality of the product, but the consistency of that quality between examples. In the case of this Pixco, maybe I just got a lucky copy that more or less works as it should?

Thanks for reading!