QHY600 Extra Short Back Focal Length Version
On the side of this adapter there is a 4mm hole to connect air pump through plastic pipe in case of the dewing glass when necessary. Because the glass window of the short back-focus version is closer to the CMOS chip, the possibility of dewing is higer than standard version in humidity situation.
QHY600 Short back-focus version is specially designed for DSLR lens users or those who has special requirment of short back focal length. This version has a special front part version which has 7mm B.F.L only. The front part includes six M2.5 screw holes arranged on a 80mm diameter roundness.
A special adapter is provided to connect the filter wheel. The B.F.L equals 12.5mm when connecting QHYCFW with the adapter. Plus the QHYCFW3L, the total B.F.L is 12.5+21.5=34mm.
Secnario A: Connect DSLR Lens (Canon/Nikon)
It's very simple--just directly connect the cam, filterwheel, Canon/Nikon lens adapter (the Nikon adapter is customized version, which is diffrent from the standard 10mm adapter). Then it can achieve the standard B.F.L of Canon/Nikon lens.
Notice: If theres no need to use filter wheel, e.g. the combo of QHY600C OSC cam+DSLR lens, we suggest you choose the standard QHY600 Photographer version.
Scenario B: Connect CFW+OAG While Short Back Focal Length
For example, if you need filterwheel and OAG to connect 55mm MPCC at the same time, then you might need this combo. Please contact QHYCCD and clarify the specifiation requirment (like "I need to coonect M48 MPCC, the B.F.L is 55mm. ", then we can provide what you need.
Notice: If it's not necessary to use an OAG, we suggest you choose standard QHY600 Photorapher version to use camera and filter wheel.
1. QHY600 Short Back-focus version supports CAA function, too. add shim between cam and top adapter for adjustment. However, each QHY camera guarantees the right center angle with professional devices before the sale. So please do not adjust CAA unless there's a problem at the front of the cam, like telescope adapters.
2.Please take a note that because the glass window of the short back-focus version is closer to the CMOS chip, though sealed window glass heating plate integrated, the risk of condensation exists. QHYCCD provides a corresponding solution to this situation, however currently it still needs a lot of experiments or facts to prove the effectivity of this solution. Nevertheless, it is recommended that users without special requirements choose the standard version.