If you are into Russian M39 lenses, I’m sure you’ve looked at the Industar-69 and thought “Wow – that would be the perfect street lens! 56mm equivalent, f2.8, super-compact pancake format, FSU street cred – I’ve got to get me one of those!” Then you’ve done a little research and found that, although the lens uses the M39 mount, it wasn’t designed for FED/Zorki rangefinder cameras, so the register distance is off and you can’t get infinity focus. Then you’ve done a little more research and found that brave folks like Hamish Gill and Brian Sweeney have come up with ways to substantially modify the lens internals to get infinity focus, but you’ve been afraid to tackle the filing, grinding and irreversible destruction required. Well, I have good news for you. Sometimes, the FSU’s notoriously loose quality control standards can work in your favor – and you may be able to hack this lens without much trouble at all. • First, check to see if your lens already reaches infinity focus (you never know – you may have a copy that has already been modified). If it does, congratulations! You are a very lucky person – stop reading this post and go buy a lottery ticket. :smile: • If the lens doesn’t reach infinity focus, remove it from your camera. Set the focus to infinity. Unscrew the three retaining screws around the focus ring and remove it by lifting it straight off. Be careful not to disturb the position of the lens block at the infinity focus setting. Take a close look at the rear of the lens block. If there are exposed threads, there may be enough travel for you to get infinity focus without any major modifications. In my limited experience, the assembly of these lenses is pretty haphazard, and the design seems to anticipate that by building a lot of travel into the focus helix. • Screw the lens block into the base as far as it will go and remount the lens on your camera without the focus ring. Are you at or beyond infinity focus? Turn the lens block with your fingers to see. If you can reach infinity focus, continue to the next step. If not, you’ll need to try this alternate approach or Hamish Gill’s or Brian Sweeney’s modifications. • With the lens at infinity focus and still on your camera, carefully slip the focus ring back on and line up the infinity focus mark. Try to tighten the three retaining screws far enough to secure the focus ring flush with the front of the lens block. If you can, you’re essentially done! You may need to adjust the aperture mark and you may also want to remove the near focus stop screw to give you closer near focus (both described below), but neither of those steps are required. • If you find that you can’t secure the focus ring flush with the front of the lens block, here’s what has happened: with the lens block screwed in far enough for infinity focus, there isn’t enough room inside the lens to accommodate the length of the three internal focus stop screws. Fortunately, the stop screws can be easily shortened. • Remove the lens from your camera and remove the focus ring from the lens. Unscrew the lens block from the base. • Locate the three focus stop screws: the near and infinity focus stop screws in the base and the common stop screw in the focus ring. • Check to see if any or all of the stop screws are protruding beyond the edge of the base or focus ring. • If so, you want to shorten the stop screws so that they do not protrude, but are just within the edge of the base or focus ring. You can do this by unscrewing the stop screws and then removing some material from the tops of the screws with a hand file or a Dremel cut-off wheel. I suggest simply removing the near focus stop screw and not shortening it for the moment, for a couple of reasons: (i) without the near focus stop screw, you can achieve closer near focus and (ii) if you really mess up one of the other two stop screws, you have a spare. • If you are good at file work or Dremel-ing, you can cut new screw slots in the tops of the stop screws after shortening them. If not, don’t worry – you can screw them back into place with needle-nose pliers. • Re-install the stop screws (leaving out the near focus stop screw if you like). Check to see that the shortened screws are no longer protruding beyond the edge of the base or focus ring. • Screw the lens block back into the base but leave the focus ring off for the moment. Mount the lens on your camera and find infinity focus. With the lens at infinity focus and still on your camera, carefully slip the focus ring back on and line up the infinity focus mark. Tighten the three retaining screws far enough to secure the focus ring flush with the front of the lens block. Check your focus throughout the full range. If you left out the near focus stop screw, the focus ring will rotate almost one entire turn and you should get a minimum focus distance of only a couple of feet. • The last step is to check the aperture mark. Moving the lens block relative to the focus ring means the original aperture mark has been shifted and probably no longer matches the iris opening. Open the iris to f2.8 and put a corresponding drop of red paint on the aperture ring. Put a drop of silver paint over the old aperture mark. • Let the paint dry and enjoy your 56mm equivalent, f2.8, super-compact pancake format, FSU street cred, perfect street lens!