A REVERSING RING is simply an adaptor with the fitting to go on the camera on one side, and a male thread to screw into the filter thread of the lens on the other. If you reverse mount the lens directly onto the camera body, the optical centre of the lens is displaced from the film, introducing a short extension. This causes the lens to focus close, and gives a fixed high magnification, and a fixed working distance. The magnification depends on the focal length of the lens, and the displacement from the film. W/A lenses give higher magnification than standard or tele lenses. In normal use, a lens has its largest element facing the subject and the smallest element facing the film. Using tubes or bellows, to give 1:1 or greater, the distance between the lens and the film is greater than between the lens and the subject. To maintain best quality, the lens still has to have its largest element facing the longest distance, and as this is now between the lens and the film, rather than the lens and the subject, the lens needs to be mounted in reverse. This is the 'proper' use of a reversing ring.
WHAT CAN I USE THEM FOR ?
Small subjects such as stamps, coins, jewellery, medium bugs, smaller flowers.
HOW DO I USE THEM ?
Simply fit it to the camera, and then screw the lens on via the filter thread. You have no focus control, so you must move the camera in and out to focus. There are no connections between the camera and the lens, as these are now at the front. You can either use manual exposure, or set the camera to aperture priority auto. Some lenses will only allow you to use a fixed aperture, but you may get some control by moving one of the exposed pins on the lens end. Some fully auto lenses such as EOS do not have aperture rings so you are unable to set the diaphragm manually. These lenses will have to be used at full aperture
HOW CAN I TEST THE EFFECT BEFORE I BUY ?
Hold any of your lenses in front of your camera so that the filter thread is close to the front of the camera body. Aim at a sheet of newspaper. Focus by moving in and out. Count the number of words/letters to gauge the field width. W/A lenses focus closer and giver higher magnification.
ADVANTAGES
Small, inexpensive accessory that fits in the pocket or gadget bag for very close work. Improves results with tubes or bellows at magnifications greater that 1:1.
DISADVANTAGES
Fixed focus point. Fixed magnification. Manual or aperture priority modes only. Some fully auto lenses (EG Canon EOS) do not have aperture rings. These must be used at full aperture.
EXTRA TIPS
To increase magnification, use SRB~GRITURN SPACER RINGS between the lens and the body. To fit lenses with different filter threads use SRB~GRITURN STEPPING RINGS. Ask us about specially made adaptors to fit filters, lens hood, or ringflash to the reversed lens
The examples shown below were taken with the standard 18-55mm zoom lens supplied with Canon digital SLR camera using a standard playing card as the target. Owing to the limitations of reversing an EOS lens detailed above, the reversing ring was made from a standard T2 mount and an SRB~GRITURN 58mm T2 insert. This gave an effective width for the adaptor of 13mm
18mm focal length closest focus 55mm focal length closest focus
Reversed lens set to 18mm Reversed lens set to 35mm Reversed lens set to 55mm
If the reversing ring you are looking for does not exist as a standard item, we may be able to make one for you.
We do have an insert adaptor that enables standard T MOUNTS to be used as reversing rings. See the reversing ring section.
