Mamiya APO-Sekor Z 500mm F6 for the astrophotography

 

The supreme APO lens Mamiya APO-Sekor Z 500mm F6. This lens is so-called medium-format (6x7).

Actually, I had purchased a ZWO full-frame CMOS camera, ASI2400MC PRO, at an unbeatable price of 30% off (!!) from the list price a while ago by ZWO campaign, but even with Canon EF300 F2.8 IS USM full-frame lens, vignetting was so bad. I thought it was necessary to use a lens for a medium-format to prevent vignetting, so I searched for a variety of lenses and found a relatively inexpensive top-of-the-line one.

This lens is a super high-performance lens that K-ASTEC praises highly. However, there is no focusing function and no way to mount the lens on an equatorial mount, so a little ingenuity is required to use it.

Chromatic aberration characteristic curves and MTF Chart by ianbfoto.com 

For focus adjustment, I obtained a mount adapter from Fotodiox that converts the Mamiya RB67/RZ67 Mount Lens to the Canon EF mount, which has a built-in helicoid.

To mount the lens on an equatorial mount, I purchased a special optical tube band (TB-89AS) from K-ASTEC (sorry, already sold-out. and he do not sell to foreign countries), which is sold on a limited basis (Incidentally, a 90mm optical tube band will match, so other companies' products are also OK).

The used lens did not come with a standard rubber hood, so I got a 105mm metal hood from AMAZON. I tuned up the hood with cutting stickers. Isn't it cool?

This is an example of astrophotography taken with the OIII and Ha FWHM 6nm dual narrow band filter SV220, to be released by SVBONY, on the 2400MCPRO. 180sec x 3 live stacked images.

Extremely good photographic image with no vignetting!!