T
thearne3
Guest
I have now collected a couple of Computar lenses (25mm and 12.5mm) and have made the unpleasant discovery that my RJ Camera C-mount adapter is not the same as the hawkpen adapter for my lenses.
The first 'shoulder' on the lenses is 30mm (no problem). The second shoulder is ~38mm, which is easily filed down to 37.2mm. However the third shoulder is 39.2mm and, unlike the hawkpen adapter, there is no 39.2mm notch in the RJ Camera adapter, so this wider shoulder must be filed down to 37.2mm as well.
I have only done the 25mm lens. I filed down the outer two shoulders so that all three shoulders add up to 3mm of total depth (measured from the base of the screw mount toward the front of the lens) with diameter less than 37.2mm. The lens appears to be fully seated, but still only focuses to about 5' max at f1.3.
Has anyone been able to achieve infinity focus with this lens and the RJ Camera adapter?? Is the issue the lens, the adapter, or am I wrong and the lens isn't fully seated?
Thanks for any insights...
Tom
The first 'shoulder' on the lenses is 30mm (no problem). The second shoulder is ~38mm, which is easily filed down to 37.2mm. However the third shoulder is 39.2mm and, unlike the hawkpen adapter, there is no 39.2mm notch in the RJ Camera adapter, so this wider shoulder must be filed down to 37.2mm as well.
I have only done the 25mm lens. I filed down the outer two shoulders so that all three shoulders add up to 3mm of total depth (measured from the base of the screw mount toward the front of the lens) with diameter less than 37.2mm. The lens appears to be fully seated, but still only focuses to about 5' max at f1.3.
Has anyone been able to achieve infinity focus with this lens and the RJ Camera adapter?? Is the issue the lens, the adapter, or am I wrong and the lens isn't fully seated?
Thanks for any insights...
Tom