Normally, a long-burning focal length of 500mm is also accommodated in a socket of 500mm length (see our 500mm lens lenses). To obtain a handy, universally applicable and compact solution, this lens has been used in a trick. The beam path is easily folded by means of two highly precise ground ring mirrors". This results in a very short minimum focusing distance of only 2 meters in addition to the compact design and the 50% higher opening - compared to a lens with the same focal length. The focus is done manually. The lens can be used (depending on the camera) with automatic or manual exposure setting.In the folded beam it is technically not possible to use an iris diaphragm. If light reduction is necessary, this is made possible simply by the gray filter (not included in the delivery), which is screwed in front of the rear lens. There is a thread M34x0.5 for this purpose. Practical: The lens does not have a fixed infinity stop. Sharpening is performed "swinging" by finding the focus point from Unsharp to Unsharp. T2 connection, tip: The T2 adapter is screwed onto the lens, then the lens is sealed. The lateral chopsticks on the T2 adapter allow after loosening a "raising" of the lens - the alignment of the index upwards. Tightening the screws again ensures reliable optics and adapters. Advantages of a full-frame lens on a camera with APS-C sensor save you time in post-processing. A variety of lens defects such as distortion, edge blur, or vignetting occur at the outside of the image. If a full-frame lens is used on a camera with an APS-C sensor, these areas are not used. Thus you get the maximum quality. This eliminates the need for additional post-processing time to correct lens errors."
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