to be an issue with some cameras modified by Hartblei to add a mirror lock-up (MLU) feature. Other cameras may or may not have this problem, so special care is advised. Common modifications of Kiev medium format cameras The vendors that sell Kiev cameras outside of the former Soviet Union often make their own modifications to the cheap and basic cameras coming from the factory. Mirror lock-up is a feature that can be added to these cameras. This removes the small amount of motion blur that can be caused by the mirror hitting the top of the mirror box just before the shutter opens, however, other sources of motion-blur still remain. This is most useful when the subject is greatly magnified (when using long or telephoto lens) or with macro photography. Some of these cameras have a really strong mirror slap, creating motion blur even when not shooting handheld, so MLU is a really useful feature if you tend to use the slower shutter speeds. The Pentacon Six-based Kievs are sometimes modified to shoot with a 6x4.5 frame size, often called Kiev 645 or similar, yielding more pictures per roll of film in a "print-friendly" rectangular format versus the original camera's square 6x6 format. But since the film feeds sideways, the 6x4.5 variant produces photos in the portrait aspect, as opposed to the landscape aspect seen in most other cameras. On the other hand, the Hasselblad-based Kievs can shoot the 6x4.5 frame size by simply using a different film back. The 6x4.5 film back is interchangeable with 6x6 backs on others, for example instant film backs, while the Pentacon Six-based Kiev frame size modifications are permanent. The original Pentacon Six lens mount on the Kiev 88CM accepts all the lenses from Arsenal, but has trouble accepting some other lenses, for example Carl Zeiss Jena Sonnars for Pentacon Six. It is, however, possible to overcome this issue by third party modifications that allow Kiev 88CM to accept all the lenses made for Pentacon Six lens mount. Kievs cameras utilizing Hasselblad-like screw mount can be modified to Pentacon Six lens mount, which is more desirable because of the greater amount on lenses available. Since the register distance of the new mount is shorter than the original one, the mount is located inside the camera body and allows to use all existing screw-mount lenses with an adapter - this is desirable, if we