Efke PL 25 M resolution / datasheet?

[Tim Povlick]

Thanks....I use a 4x5. It does seem like th Adox Pan 25 is available on Freestyle Photo, although I haven't heard of them before.

I had not heard of this film either but so far it seems very good, although I may stick with the PanX-II (will decide after I see how the Adox scans).

[QUOTE=dh003i;509042]The red spectrum goes to 700 nm, but from looking at a color-table, it looks like what I'd consider a normal red (as in the R in RGB or the "red" in HTML or most computers) is around 650. Are the red's past that in near-IR?

From experience with film based astrophotography work, it seemed Kodak would always reformulate a color film once they found out it worked well in astrophotography. The H-alpha at ~650nm is very important for nebula images. It seemed ability to image at 650 hurt the portrait ability of the film (image did not look like what the eye was seeing). I recall at ~650n, eye sensitivity is down around 10% so I could see their point. It does seem this starts the near IR region.

I presume that by 400-650, that means it has absolutely no sensitivity beyond 650, as that's the way the Ortho 25 was from looking at it's datasheet (for Agfa Ortho 25, not Rollei).

That's the way I read the datasheet too. Once a film was reformulated to remove the 650nm and longer wavelength sensitivity it became useless for astrophotography. You could expose for an hour and get practically nothing of the nebula.

Good luck with the RGB, it's interesting. I tried it with 6x7 and was able to stack the images with an astro program that made it easy to align and gave a lot of control over the final image color. There is also L-R-G-B where the L is a luminance image (a full spectrum B&W).

Best Regards,
Tim

[dh003i]

I had not heard of this film either but so far it seems very good, although I may stick with the PanX-II (will decide after I see how the Adox scans).

Are you using 4x5 PanX-II negatives? Where do you buy them from, if so? Also, why'd you recommend the Adox over PanX-II for the tri-color exposure process? It seems like PanX-II gets the entire spectrum, with extended red-sensitivity (from the datasheet). It also seems like it has no reciprocity compensation required for exposures up to 1,000s (but are required for 1/10,000 sec):

"No exposure or development time adjustments are required
for exposure times from 1,000 second to 1/10 second. At 1/
10,000 second, increase the development time by 20 percent."

That's copy & pasted from the datasheet. Unless there's a typo.

The red spectrum goes to 700 nm, but from looking at a color-table, it looks like what I'd consider a normal red (as in the R in RGB or the "red" in HTML or most computers) is around 650. Are the red's past that in near-IR?

From experience with film based astrophotography work, it seemed Kodak would always reformulate a color film once they found out it worked well in astrophotography. The H-alpha at ~650nm is very important for nebula images. It seemed ability to image at 650 hurt the portrait ability of the film (image did not look like what the eye was seeing). I recall at ~650n, eye sensitivity is down around 10% so I could see their point. It does seem this starts the near IR region.



That's the way I read the datasheet too. Once a film was reformulated to remove the 650nm and longer wavelength sensitivity it became useless for astrophotography. You could expose for an hour and get practically nothing of the nebula.

Good luck with the RGB, it's interesting. I tried it with 6x7 and was able to stack the images with an astro program that made it easy to align and gave a lot of control over the final image color. There is also L-R-G-B where the L is a luminance image (a full spectrum B&W).

Best Regards,
Tim

[Tim Povlick]

Are you using 4x5 PanX-II negatives? Where do you buy them from, if so? Also, why'd you recommend the Adox over PanX-II for the tri-color exposure process? It seems like PanX-II gets the entire spectrum, with extended red-sensitivity (from the datasheet). It also seems like it has no reciprocity compensation required for exposures up to 1,000s (but are required for 1/10,000 sec):

"No exposure or development time adjustments are required
for exposure times from 1,000 second to 1/10 second. At 1/
10,000 second, increase the development time by 20 percent."

That's copy & pasted from the datasheet. Unless there's a typo.

I am using the PanX-II in 8x10. I purchased a 200 foot spool from HAS Imaging in Dayton, OH-USA earlier this year. So happens I cut 20 sheets last night from the spool and it looks like I finally have the technique down as the scrap pieces are all the same size (except one). I 100% agree with your points about PanX-II but mentioned the Adox Pan 25 because of availability in sheet format whereas the PanX-II is not. FYI this is a discontinued film now, so once it's gone --it's gone.

I have read on this forum that Adox Pan 25 is really Rollei Pan 25. From the Freestyle product description the Adox Pan 25 has spectral sensitivity: 400 – 650nm. Personally, I believe this should be enough of the deep red spectrum for RGB (based on film data sheets, such as Fuji 160C / 160S where sensitivity drops by 650nm).

Best Regards,

Tim

[mcfactor]

Hi, I can't really comment on the spectral sensitivity of Adox 25, since I have only used it for my own personal work, not for scientific test. However, I agree with Tim in that it does seem sharper than Efke 25 and seems to have "normal" spectral sensitivity. It is also incredibly fine grained. I had also wondered about how this compares to Rollei Ortho. I would be highly surprised if the resolution of Ortho was that much higher than Adox 25.

[dh003i]

mcfactor,

Do you have any information about the reciprocity failure specs on Adox or Rollei Pan 25 film?

The datasheet I have is very thin (just one page).

[mcfactor]

I don't. I do not usually do very long exposures. sorry.

[77seriesiii]

I think for the differences between Efke and Adox see this thread:

http://www.largeformatphotography.in...highlight=adox

I have shot with both Adox and Efke in 4x5 (25 iso version) and have been very happy with both. As far as differences, have not noticed any other than the notch is cut differently. I have not printed any yet...missing that side of my 'dark room' AKA bathroom so that is where the differences may shine.

./e

EDIT: For reciprocity Efke is out there. Its fun to shoot and people freak out when they notice I am taking a shot, talking with anyone, walk in front of the camera, etc. Occasionally, I get the "when are you going to take the shot?" "Doing it now and I am 5 minutes into a 15 minute shot" With a big smile on my face. They usually walk away shaking their head and their expression kinda says "How sad, I wonder when he goes back to the special home."

[EdWorkman]

Tim
My google search for HAS Imaging was fruitless. Do They have a website please?

[Tim Povlick]

Tim
My google search for HAS Imaging was fruitless. Do They have a website please?

Hi Ed,

Sorry for delayed response, just caught this.

The correct name is HAS Images

http://www.hasimages.com/

I talked with Ed at HAS and they have about 75 spools (PanX-II) left.

Best Regards,

Tim

[Pere Casals]

There is an option yet mentioned (Don Hutton) in this thread I support: ADOX CMS 20 film.

http://www.adox.de/Photo/adox-films-...ii-adotech-ii/

Not like Efke... but perhaps it would like you as a HiRes film it is.


In case you don't know this film, I would say:

It has 800 lppmm (line pairs per mm, so 1600 lines). http://www.adox.de/Technical_Informa...structions.pdf

Special developer has to be used, Adotech II to go straight, or POTA, etc. Common developing would render extreme contrast.

There is no need for a very high ressolution film if your lens do not has it, as in practice real 60 lppmm (high contrast) it's a lot, you would need something like this glass to go beyond after high lppmm:

http://www.ebay.com/itm/Huge-Carl-Ze...-/221938551851

It weights 30kg for a 150mm focal, and not cheap.


But CMS 20 is virtually grainless, and records every drop of optical performance from your lens... and has a nice particular mood!!!

See:

https://www.flickr.com/photos/558734...57631623052598
https://www.flickr.com/photos/558734...125592977@N05/

Shot it al ISO 20 for dull illumination, but ISO 12, as much, if not.

For the spectral sensitivity you can use filters to make it work like you want, but it reaches just 650nm, see above pdf link


In my case, I've shot some rolls to learn this stuff, now I've just started shooting 4x5 sheets. It's a difficult film...


Regards