Flange focal distance

Or: why you should try a Nikon lens on a Canon body

Coffeeground and simon.hucko made an interesting discovery here about the focal distance of the different camera manufacturers lenses and bodies. You can get a more technical explanation here on Wikipedia (as well as a list of all the other manufacturers and their focal distances), but basically Canon lenses are designed to focus on the Canon sensors which are 44 mm from the mounting flange (the metal ring on the camera and the rear of the lens). Nikon lenses are made to focus on Nikon sensors, which are 46.5 mm from the back of the lens.

This is interesting to freelensers because it means if you use a Nikon lens on a Canon body, you will be able to focus on things that are much further away, while still getting the beautiful bokeh and other freelensing effects. You don’t even need an adapter, since you’re just holding the lens in place.

Help – nothing is in focus!

Freelensing works best with prime lenses (50 mm is a favourite). Telephoto and zoom lenses can be used, but they will have more vignetting and seem to be harder to focus. Also, because most zoom lenses only start at f/4 or f/5, they can’t let as much light in (compared to an f/1.8 50 mm, for example), which may result in darker photos.

Before removing the lens it is best to set the focus on “infinity” – for two reasons. Firstly, you are more likely to drop the lens if you’re fiddling around trying to change the focus while holding the camera and lens separately. Secondly, setting the focus on infinity will let you control the focus more finely by using the tilt of the lens and will let you actually be able to focus on things more than a few feet away.

Freelensing doesn’t work with my Nikon!

If you use a Nikon camera for freelensing, you may need to set the camera to Manual or Aperture Priority mode. (Thanks to Eddie Barksdale for discovering this)

Nikon G lenses also close down the aperture blades when disconnected from the camera (the D lenses don’t do this – thanks kristopherlundborg), so if your photos are coming out very dark, this might be the reason. You will need to make something that will hold the aperture lever on the back of the lens in the open position. A small piece of blu-tack or cardboard seems to do the trick. (Thanks to ted @ndes and Joseph Yarrow for discovering this)

Narflet also reports that freelensing can make the metering on her Nikon a bit unreliable: “I often have to boost +1-2EV”. If your photos are still coming out dark after fixing the aperture level problem, this might be the next step to take.

Will freelensing work with my Sony?

In your camera’s menus, look for the “Release w/o Lens” option, and make sure it is enabled. If you can’t find that option in any menus, try setting the camera to Manual mode (M on dial) and also set the camera to manual focus (thanks ted @ndes).

Similar to the Nikon lenses, you may also need to make something that will hold the aperture lever on the back of the lens in the open position. If your photos are very dark while freelensing, this is likely the reason. A small piece of blu-tack or cardboard should be able to hold the lever and keep the aperture blades open.

Olympus, Pentax and others

I haven’t heard any problems from those using Olympus or Pentax cameras. It seems the Olympus and Pentax lenses, like the Canon ones, don’t auto-close the aperture blades when disconnected.

Anyone using a Panasonic or other camera for freelensing? Did it work? Any problems? I’d particularly like to know if anyone has tried it on any of the Micro Four Thirds system cameras. Let me know in the comments here or on the Flickr group discussions page.

What is Freelensing?

Photos taken with the lens detached from the camera but held in place and moved around to focus. This also lets extra light in sometimes causing light leaks and giving a vintage look and feel.

Freelensing can also:

• Give extra bokeh by shrinking the area in focus (aperture is 0)
• Allow for super macro shots
• Produce ethereal lighting by allowing stray light to get in to the sensor
• Make delicious light leaks
• Create tilt-shift effects

How do I do it?

If you just want the tilt-shift effect, you can detach the lens, but hold it in place against the camera. Slightly move the lens left, right, up or down.

It’s easier if your camera has a “live view” so you can see what it looks like, but it’s not too much harder with the view finder.

You only need to move the lens a few millimetres (fractions of an inch), and doing it this way, there’s not much risk of dust getting in to the sensor.

If you want lightleaks or the super-macro kind of effect, you will need to hold the lens a little bit further away (probably no more than a finger width, though). This is a bit more risky if you’re worried about dust, so try not to hold the lens away from the camera for too long and only do it in a dust-free environment.

For light leaks, I’ve found it’s best to be in a fairly dark room, with a big window in front of you. This lets the outside light get in to the camera (i.e. not through the lens, but just going straight in to the gap between the lens and the camera) but limits the ambient light getting in (which makes the photos less defined).

Will it work with my (SLR) camera?

Canon – Yes

Nikon – Yes – You have to put the camera into manual mode (thanks Eddie Barksdale)

Sony – Yes – In your camera’s menus, look for the “Release w/o Lens” option, and make sure it is enabled. You might also need to make something that will hold the aperture lever on the back of the lens in the open position (thanks ted @ndes)

If you’ve had success with your camera and it’s not on the list, let us know in the comments here or on the freelensing forum on Flickr.

Examples

See more on the Flickr Freelensing pool.