Cooled CCD Camera

[Ho Pei Jiun]

Dear Sir/Mdm,

I have a Cooled CCD camera (APOGEE ALTA U4000) which has 2048 x 2048 number of pixels and each pixel size is 7.4 micronmeters. The Cooled CCD camera comes with a F-mount lens adapter. The back focal distance of the cooled CCD camera with the F-mount lens adapter is 46.5mm.

I need to capture a rectangular target object which has the size of 80 mm (W) x 60 mm (H) into the above mentioned CCD camera within working distance of less than 30cm. The width of the captured image should cover up almost the width the CCD camera sensor. Additionally, the captured image must be sharp, clear and does not have any 'curvature' effects at the edges.

Now i'm looking for the suitable lens solution for my above application. Can anyone advise me what are the suitable lens i should use?

I tried one method which is to attach a 28mm f2.8 lens on the cooled ccd camera as per normal. Then i mount a 150mm large format lens in a reverse position on the front of the 28mm f2.8 lens (i.e. the both lens are front to front within a close distance of 10mm). The distance between the 150mm large format lensboard flange and the 80mm x 60mm target object is about 150mm, as similiar when the 150mm large format lens is mounted on a conventional large format camera . The 28mm lens is then set to infinity.

However, for the above mentioned method, the image i captured is very, very blur. I could not figure out what goes wrong with this method. I also appreciate if someone can suggest and advise me does this method works.

Looking forward to your replies urgently. Thank you very much.

Best Regards,
Ho Pei Jiun

[Henry Ambrose]

If by "F Mount" you mean that it is Nikon F mount then why not use a Nikon 60 or 105 macro lense? Either will focus down to 1:1. Do you have to be 30cm from the subject? If so, the 60mm lense will get there I think. If you can be further away the 105 might be flatter (not much though).