Post by BillW on May 9, 2014 20:49:11 GMT
Hi,
Been a busy day on the lens front! Just before leaving for Tenerife I bought what was described as a "job lot" of surplus CCTV equipment.
On the ebay photos a couple of lenses caught my eye. I was looking for something like these for NLC observing on colour cameras. A large box from ebay was waiting for me on my return.
I took a chance expecting there to be three or possibly four of the lenses I was looking for given the pictures online. These were Computar 1/3 inch format 5.7mm to 34.2mm f1 zoom lenses.
Turns out that there were 11 in the box! All unpackaged and rattling around. A couple have the rubber focus band missing and a couple more have some cosmetic damage but they all cleaned up nicely and all work. These were pricey lenses when new.
Anyway to cut a long story short when testing them on the 902's they exhibit the "tunnel effect" as they're for a smaller sensor format but the monochrome focus looked really good. To get focus I had to wind out the adjustment ring on the camera body. It has just occured to me that this is the same effect the washer does on the fast f0.8 lenses when fitted with the IR corrector. So if you want to lose the washer you can. Loosen the ring with the tiny allen key and wind it out a turn or two. plug the lnes in and see how it looks. Might take a couple of goes unplugging due to the cable wrapping up but then you can lock the ring in place and dispense with the washer.
I think the washer must have been for cameras without this adjustment option. These f1 lenses lose a bit of frame at the 5.7mm setting but with the decent focus (and I think they're also a touch faster at f0.9 in reality by measurement) they might make acceptable meteor lenses. Turns out they also have a removable IR corrector that screws into place which can be removed for colour. (A slight edit, In colour with the IR optic on the images are a touch softer but it still works.)
They work great on the colour cameras which have the smaller sensor so it's been a result, just a pity they're for the smaller format, would have been the bargain of the century!
I'll post some pics when I get some clear skies to do some tests.
Cheers,
Bill.
Pic of the lenses whilst I was cleaning them. For size comparison, the smaller of the other two lenses in the picture is a normal 8mm f1.2 for 1/3 in format.
Been a busy day on the lens front! Just before leaving for Tenerife I bought what was described as a "job lot" of surplus CCTV equipment.
On the ebay photos a couple of lenses caught my eye. I was looking for something like these for NLC observing on colour cameras. A large box from ebay was waiting for me on my return.
I took a chance expecting there to be three or possibly four of the lenses I was looking for given the pictures online. These were Computar 1/3 inch format 5.7mm to 34.2mm f1 zoom lenses.
Turns out that there were 11 in the box! All unpackaged and rattling around. A couple have the rubber focus band missing and a couple more have some cosmetic damage but they all cleaned up nicely and all work. These were pricey lenses when new.
Anyway to cut a long story short when testing them on the 902's they exhibit the "tunnel effect" as they're for a smaller sensor format but the monochrome focus looked really good. To get focus I had to wind out the adjustment ring on the camera body. It has just occured to me that this is the same effect the washer does on the fast f0.8 lenses when fitted with the IR corrector. So if you want to lose the washer you can. Loosen the ring with the tiny allen key and wind it out a turn or two. plug the lnes in and see how it looks. Might take a couple of goes unplugging due to the cable wrapping up but then you can lock the ring in place and dispense with the washer.
I think the washer must have been for cameras without this adjustment option. These f1 lenses lose a bit of frame at the 5.7mm setting but with the decent focus (and I think they're also a touch faster at f0.9 in reality by measurement) they might make acceptable meteor lenses. Turns out they also have a removable IR corrector that screws into place which can be removed for colour. (A slight edit, In colour with the IR optic on the images are a touch softer but it still works.)
They work great on the colour cameras which have the smaller sensor so it's been a result, just a pity they're for the smaller format, would have been the bargain of the century!
I'll post some pics when I get some clear skies to do some tests.
Cheers,
Bill.
Pic of the lenses whilst I was cleaning them. For size comparison, the smaller of the other two lenses in the picture is a normal 8mm f1.2 for 1/3 in format.
