Copying negatives with Ohnar reverser SR

Trespassing on serious ground here but i hope someone can help. I have the usual many thousands of film negatives which I want to sort and pass the best on to offspring. Not being a Microsoft man my old film scanner is useless. I have recently bought the Ohnar and have a Pentax 42mm to K/R to couple onto my Pentax K10. But of course I forgot the difference in aspects and the Ohnar is only copying 2/3rds of the negatives. Has anyone any experience of modifying the Ohnar to suit a digital camera? Have lathe and am contemplating removing a secton of the parallel tube and sliding the two halves into an outer tube to get the correct optical arrangement but thought I would ask before committing.

TIA

Ken

Have you checked Vuescan's list of supported scanners https://www.hamrick.com/vuescan/supported-scanners.html to see if your scanner will work with Vuescan?
Some scanners listed require the manufacturer driver which may not be available for the current OS.

Thank you shutterfinger. Yes I downloaded VueScan but there is no linux driver for my PrimeFilm 7250u.

Hi Ken, your Ohnar is designed for 24x36mm negative and regular SLR or full frame digital camera. Your Pentax is APSC size. Most likely you need to extend distance between negative and sensor (extension tubes or bellows) but question is: can you then obtain proper focus?? Also how good is Ohnar optics?
I made DSLR scanning rig from Nikon bellows and with APSC camera and had to use 75mm lens to have full coverage of the negative and sensor. Now i can copy 6 strips of 6 negatives in around 10min. To scan it I needed at least half a day

Ken Parkes said:

Trespassing on serious ground here but i hope someone can help. I have the usual many thousands of film negatives which I want to sort and pass the best on to offspring.

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If you have not reviewed the process of converting digitized color negatives to positive images I suggest you do especially for that quantity. If you have the proper setup, capture could be minimal. The post work can be substantial.

gorbas said:

I made DSLR scanning rig from Nikon bellows and with APSC camera and had to use 75mm lens to have full coverage of the negative and sensor. Now i can copy 6 strips of 6 negatives in around 10min. To scan it I needed at least half a day

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Obviously a mild exaggeration when it comes to scan times but of course this depends on the scanner. My Coolscan 5000 will scan a 35mm frame at 4000dpi with dust and scratch removal automatically in less then 50 seconds - about 30 seconds with ICE turned off. It can automatically scan a whole roll. There is even a 50 slide adapter which I don't have since I never mounted my slides. My Epson V700 will do the same under 3 minutes each frame - up to 24 frames at a time. There are other slower scanners that may take 5 minutes per frame.

I also have the Nikon & Pentax bellows setup to copy film. For slides and b&w, my post work after a DSLR capture - without dust and scratch removal, can be pretty minimal. However, for color negative work, each frame can easily surpass even the slowest scanner. I've been meaning to try the Nikon D850 for this because it has a built-in color negative to positive conversion. Hopefully it will be equal to the Coolscan+Nikonscan when it comes to quality of the conversion. Unfortunately DSLR capture has no dust & scratch removal and that can be very tedious. And the higher the capture resolution, the more obvious the scratches and dust particles become.

Thank you all for your valuable comments. I need to mull things over and try a few ideas tomorrow. Will respond PM. GMT time.

Regards, Ken