Does anyone know of a 4x5 resolution target?
I am looking for a 4x5 film transparency target to use when I adjust my scanner focus with a variable height wet mount holder. I see 35mm format, but don't think it would work well to really set focus. I could be wrong though, but working with a target the same size as what I shoot would make me feel better and I think would work better.
Any thoughts on a 4x5 focus/resolution target and where to get? I can't find them, just the 35mm ones.
Re: Does anyone know of a 4x5 resolution target?
I suppose I could order acalibrated target of choice and photograph on 4x5 with my camera. Assuming I get everything right, then I would have a target that I can use to set focus on my scanner.
Re: Does anyone know of a 4x5 resolution target?
I was looking at this NBS 1952 Resolution Test Target, 3" x 3" from https://www.thorlabs.com/thorproduct...number=R3L3S6P while it is 1.5mm thick and I would need to be a tad creative to wet mount, I could shimm glass in betterscanning holder to put the target at the right distance (so it ends up in the same spot/distance from the scanner glass as a wet mount piece of film would. Or I can photograph it, develop and use that as my target.
Lasersoft is looking into seeing if they can make a 4x5 target for me. Sales thought so, but is checking with main office in Germany so won't know till tomorrow.
Re: Does anyone know of a 4x5 resolution target?
Have you checked with Edmund Optics?
They have over 100 different targets, from $6 to over $1200, and sizes from microscope slides to 8"x10".
https://www.edmundoptics.com/search/...tion%20target#
- Leigh
Re: Does anyone know of a 4x5 resolution target?
Is there a reason you need a resolution target, rather than just taking a good negative you have and adjusting for maximum scan quality? Are you trying to quantify the performance of your scanner?
Re: Does anyone know of a 4x5 resolution target?
Yep, I looked and they have a target I am interested in https://www.edmundoptics.com/f/high-...rulings/12727/ in either 3x3 or 4x4 like 100 lpl/mm. Would be same issue, mount to ANR glass, shim ANR to proper height and go from there. I suppose I could mount target backwards to to get close to actual slide position without shimming ANR glass.
The film target has the advantage in that I can wet mount it for focus adjustments and have that based on the same optical as an actual 4x5 film sheet when mounted.
Re: Does anyone know of a 4x5 resolution target?
Steven, you can DIY your own 4x5 resolution target.
You need a USAF 1951 glass slide, and a sheet of ADOX CMS 20. Then you make several contact copies of the slide in several places of the CMS 20 sheet. The film emulsion side in contact with the printed side of the slide...
CMS 20 is in fact microfilm material, so it can outresolve anything (until 800 lp/mm). $159 for 50 Sheets, 4x5". You can develop the contact copy with any common developer, as you need no greys.
What's for the slide you may find cheap ones at ebay (search USAF 1951 glass slide), mine it's good until some 250 lp/mm, it was not reaching what was said, inspected with a microscope, but good enough for what I wanted it, most of the cases you can make an offer, try offering the half, some $40...
At the end you may need a resolving target sporting under 60 Lp/mm for the scanner, both the cheap slide and the CMS 20 are able for that. And you will also have 49 sheets of CMS to get some fun...
Re: Does anyone know of a 4x5 resolution target?
Quote:
Originally Posted by
Steven Ruttenberg
Would be same issue, mount to ANR glass, shim ANR to proper height and go from there.
Huh?
The emulsion side of the original should be in contact with the scanner glass.
That shouldn't produce Newton's rings.
- Leigh
Re: Does anyone know of a 4x5 resolution target?
Quote:
Originally Posted by
Oren Grad
Is there a reason you need a resolution target, rather than just taking a good negative you have and adjusting for maximum scan quality? Are you trying to quantify the performance of your scanner?
I tried using a well focused image, but the results were not as good as I wanted. Using a target that is calibrated and of known quality i can more accurately set the focus. In some respects I can fi d the best scanner resolution that will also give the sharpest image. More importantly it is just something I want to do.
Re: Does anyone know of a 4x5 resolution target?
Quote:
Originally Posted by
Leigh
Huh?
The emulsion side of the original should be in contact with the scanner glass.
That shouldn't produce Newton's rings.
- Leigh
I use a better scNning fluid mount set up and wet mount my film to the anr glass film faces scanner glass. It is several mm abo e the scanner glass as that is wbere the focus point is set. G Epson for scn i v 5x7 and smaller formats.