Improving A Samyang 800mm With A Tuning Key And Some Cardboard

The Samyang mirror 800mm f/8 [B&H | Amazon] has an incredible money-to-mm value. Sadly is developed a reputation as an impossible lens to focus and a to be blurry to the point that there is no micro contrast and no low contrast in the image.

Improving A Samyang 800mm With A Tuning Key And Some Cardboard

Photographer Morten Øen shared two tips with us to give this lens an overall boost and really squeeze quality out of that $180 the lens costs.

Adding a Focus Tuner

Improving A Samyang 800mm With A Tuning Key And Some Cardboard

One thing that is pretty hard with this lens is focusing. It is so delicate that it is almost impossible to focus by hand. It’s native precision is too low. Morten cleverly attached a guitar tuner key to the lens and geared down the focus to about 1/16 (or 1/32). This allows some pretty precise focusing. Here is Morten’s Explanation:

The Focus Tuner (FT) is fairly easy to use. It uses a set of rubber bands, so you can just tilt the rubber wheel and focus normally so you are roughly in the ball park of what you are shooting. Then just lower the wheel down and start turning the tuning peg. Because I use a guitar tuner it is geared down to 1/16 or 1/32, then I have total control.

To get good traction I added a clothe hanger to get the rubber band directly above the focusing wheel. It might not be necessary for all lenses, but it helps a lot with this one. The construction is easy; 1 guitar tuner, 1 piece of wood, a rubber door stopper, a nail through the door stopper to prevent it sliding off the guitar tuner, a cloth hanger or nail or screw to get momentum on the door stopper, and a rubber band.

Improving Contrast

Improving A Samyang 800mm With A Tuning Key And Some Cardboard

The Samyang 800mm has a fixed aperture of f/8. I use the following method to close down the aperture, which both improves contrast and increases depth of field. (though it does kill some of the light coming in).

The way that this is done is by adding a secondary aperture where the filter usually goes (pretty similar to our Bokeh Masters Kit), which stops down some of the light:

The aperture is self explanatory; just two sheets of black cardboard or plastic, and some cut away. The out-of-focus bokeh highlights will get the exact shape of the hole, so make them with great care, and make sure you get a perfect hole at the f.22 setting

See this comparison to get an idea of the changes (click to enlarge):

Bottom right is the best of 5 images without the focus tuner. It is just the photo we are used to see with the Samyang mirror lenses. On the top right is the same photo taken with my focus tuner at f.8. Lower left yet the same image, but stopped down to f/11 and upper left is f/16. I wanted to add another one at f/22 which is the sharpest, but shutter speed was too long for this overcast day. f/16 is good enough, and gives the lens some micro contrast it never had before:-) These are 100% crops, and the target is 3 km away. Camera is a Canon 60Da (for astronomy) so the lens is actually equivalent to 1200mm lens or so.

Improving A Samyang 800mm With A Tuning Key And Some Cardboard

Here is the full crop:

Improving A Samyang 800mm With A Tuning Key And Some Cardboard

And a photo of the moon at f/16 using the focus tuner.

Improving A Samyang 800mm With A Tuning Key And Some Cardboard


It is nowhere near the $10,000 glass, but for $180 it’s good enough for me. The low weight and short barrel makes it far better than my 400 f.5.6 and 2x TC For astrophotography

  • Oisin Conolly

    Wow….just. Wow.
    What an improvement. I might actually get one of these lens now

  • david d

    Larger photos would be nice in order to see what’s going on with the tuner.

  • Andrew

    I agree..those images are way to small to be much help. I do understand, but still. could you post larger versions?

  • Morten Øen

    The first image with the 4 100% crops shows it all. Just click on it. It gets larger. The sharpness is the same from corner to corner with a crop sensor camera. It looks almost just as good on FF. One of the benefits of a mirror lens. I also use a lens shade. You can make one or buy one on eBay. The lens shade boosts contrast, the aperture boosts sharpness (strangely not the contrast), and the FT boosts focus accuracy. All of these improvements are good enough for 99% of stuff you want to take pictures of. Besides, handling is not as critical with a mirror lens. You don’t need that 20kg tripod and mirror lock-up, and extra weights to dampen vibrations. Camera is dead steady after a 1/2 sec. after touching it, because the lens is very short and very light. Here is a slightly larger image too (if it works)

  • Morten Øen

    Ups! Missunderstood there. Sorry. The tuner is just a guitar tuner. You stick it through a hole in a piece of wood, just like on a guitar. And just like on a guitar it has to go through in order for the rubber wheel to be mounted. The wheel has to be lower than the wood. The wood needs to be curved for better traction. A screw or something should be mounted above the wheel for better momentum or pressure or traction. If you know nothing about instruments, just buy a guitar machine tuner, and you will understand how to use it as soon as you hold it in your hand :-) It costs just $2, so It’s worth the risk. Or you can be classy and buy an original Fender or Gibson tuner …

    • wooac

      Are you using acoustic or electric guitar tuning keys? The focus ring on my Samyang 500mm is pretty narrow. Any thoughts on something more permanent than rubber bands? Any pointers on a lens hood?

      • Morten Øen

        I’m using Fender style electric tuners, but any will do if they come as a single tuner. Tuner for classic nylon string guitar will not fit, and they come mounted three in a row. As for lens hood just find the front filter diameter and find it on eBay. I gave $16 for a metal one at 105mm from USA.

        • Morten Øen

          … and I forgot about the rubber bands. A permanent version will have to be a metal roller, or rack and pinion, and the anchor point screwed in place on the focus ring with a spring steel plate on the back (in order to be pushed back for rough focusing). Thought about it, but does not need it. I do mostly astro photography. For close focus the lens only need a lens hood and aperture control to be stellar 😉

          • wooac

            Thanks. I’d almost given up on this lens.

  • Morten Øen

    Here is another image of the tuner. The groove in the wood is not necessary. It was for the rubber band, but not enough force was applied. Thats when I used the clothes hanger. An ordinary screw with a slight bend will do just fine.

  • ikke

    Thanks! another happy person here!!!

  • Scott

    Anyway you could show a photo of the new aperture/filter on the camera? I love the idea but not sure how to impliment it.

  • Brett Martin

    This reminds me of a Video DSLR follow focus, though with a lower gear ratio.

  • digit

    Can you add some additional images of the devise on lens and on making the filter.