Reciprocity for Android


I wrote an Android App last year that I felt I needed myself when I was out and about in the field photographing long exposures. I’m happy that it has now more than 2000 active installs and I have taken all comments into account and released an updated version.
As you are well aware of, most films do need correction of the exposure time for reciprocity failure to avoid underexposing your negatives for exposure times of over a few seconds. This really gets important for night photography, when using filters and for Large Format or pinhole photography. All information is contained in the App so no data connection is needed when you’re on a photo shoot abroad, on top of a mountain or in the deep countryside without any connectivity.
I do not miss the folder with printed and weather-beaten PDFs with tables of exposure correction information for the different films that I had to rely on before. 🙂

The Reciprocity App has the following features:

  • Easy to use and usable on Android devices of most sizes.
  • Lots of B&W, colour and slide film included in the App, and this list is growing with every update.
  • Include filter factors in the exposure time calculation.
  • Include bellows extension in the exposure time calculation.
  • Built-in timer to use the calculated exposure.

See the screenshots below.

Ease of use:

Growing number of films supported:

Details about the calculation:

Built-in timer:

Reciprocity formula

In addition to the film manufacturer supplied reciprocity information, I used the findings of Howard Bond from his article in the Photo Technique magazine which had been formulated into an easy formula by Patrick Gainer.

It is a simple App, but packed with the reciprocity details of most black and white films currently being sold and a growing number of colour and slide films. Works fine on new and old Android phones as well as on Android tablets.
It’s free, make sure to grab it!

Redscale film

Redscale film is easy to make if you have a dark room or a change bag: Simply take all of a C-41 film out of the canister, cut it off and tape it back, back to front, and spool it back into the canister so the film will be exposed on the wrong side. All layers of C-41 film are sensitive to blue light, so the blue layer is positioned on the top normally absorbing the blue light. The result of using redscale film is a clear colour shift to red due to the red-sensitive layer of the film being exposed first as it is now on top.
You would need to overexpose a few stops to avoid having just everything in red as overexposure allows light to reach the less sensitive green and blue layers of the film. And if you are using expired film for this, you would need to overexpose even more. It is a bit trial and error.

Aoi-ike and flash photography

Aoi-ike or Blue pond is a relatively new tourist attraction around Biei, Hokkaido; very beautiful with dead trees in a blue pond. Of course the pond wasn’t blue frozen over, so the choice for black & white film was no issue.

131 seconds exposure om Fuji Neopan Acros 100 at EI 100, developed in HC-110 dilution E for 7 minutes. Agitation: 2 inversions every 30 seconds.
131 seconds exposure om Fuji Neopan Acros 100 at EI 100, developed in HC-110 dilution E for 7 minutes. Agitation: 2 inversions every 30 seconds.

The scenery was lit up at night making it a magnet for photographers who, probably because they wanted to catch snowflakes in the foreground, couldn’t stop using their flashes resulting in images of walls of white in the heavy snowfall with no trees visible. I guess you need to know what you’re doing to get the effect right and probably using your flash in automatic mode wasn’t the correct way as it was pretty much pitch dark even with the lights so the flashes were bright like nuclear explosions. (A “feature” of a DSLR on a tripod is that everybody standing behind you gets to see the result on the tiny screen and I checked out the results of quite a few of my fellow photographers — it didn’t look like any of them had any “keepers.”) 🙂
Anyway, a lot of my long exposures were ruined by the flashes and I tried to out-wait them for an hour or so, but in the end I gave up and returned at another night which turned out to be exactly the same. In the end I returned during the day time as the pond was just a couple of kilometers from our hotel at Shirogane Onsen on the way to Biei.

SMC Pentax-M 50mm f/1.7 lens

During my last trip to Japan I brought my trusty Pentax 645NII medium format camera but also my Pentax MZ-S SLR camera with just one lens and in a pouch so that I could easily carry the camera around in my coat pocket and have always something available even when bringing along the rucksack with the Pentax 645NII was too tiring. I had only brought Kodak TRI-X on 35mm and had started to shoot it at EI 800 to give me possibilities at night and for street photography.

SMC Pentax-M 50mm f/1.7 lens
SMC Pentax-M 50mm f/1.7

As I said, I had only brought one lens for this camera and in that case I prefer to take a 50mm prime lens. I have a pretty good Sigma 50mm f/2.8 autofocus lens but this time I decided to take the SMC Pentax-M 50mm f/1.7 lens that I had bought together with my Pentax ME camera back in the 1970s. The SMC Pentax-M 50mm f/1.7 was really an amazing lens at the time and it still is awesome with great sharpness and contrast, and performing still acceptably well at f/1.7. See Ken Rockwell’s site for a review of this lens. The great thing with Pentax cameras is that even a modern SLR as the Pentax MZ-S will work perfectly fine with any old lens with a Pentax bayonet mount, no matter how ancient.

At first I was a bit afraid that a manual focus lens was going to be troublesome or too slow, but it was very easy to use and the focus indicator of the camera was a great guide to know when the focus was correct. I’m not really quickly sneaking photos of people, I prefer to engage them and then take their photo so it was not an issue at all. All in all, I think I made the right choice, the f/1.7 aperture was very welcome and the resulting shallow depth of field was really helpful making these photos work.

S-M-C Takumar 6X7 105mm f/2.4 lens

Foma Fomapan 400 at EI 400, developed in HC-110 dilution E for 10:30 minutes, agitation: 2 inversions every 30 seconds Foma Fomapan 400 at EI 400, developed in HC-110 dilution E for 10:30 minutes, agitation: 2 inversions every 30 seconds

The S-M-C Takumar 6X7 105mm f/2.4 lens in its three different yet optically identical incarnations is probably the most recommended lens for both the Pentax 6×7 and the Pentax 645 series of medium format cameras. I never really understood this, the SMC Pentax 67 90mm f/2.8 lens that I already owned is on paper not that different if you only consider the aperture and focal length.  Yet the 105mm at open aperture has an amazing and quite a unique bokeh which makes it great for portrait photography out in the field.

I’ve only tried out the lens on my Pentax 67II so far and I’m keen to use this lens on my Pentax 645NII via the affordable Fotodiox adapter I picked up earlier. I love all my other Takumar lenses, if it works out as well on my Pentax 645NII, this lens will be a keeper!

Dancers in the fog

This year we visited the same area in the Vosges as last year. I like doing that, being able to visit the same places again under different circumstances. The old mirabelle trees that I photographed last year were still there and this year I visited the location in a thick fog.

ROLLEI PAN 25 @ EI 25; developed in HC-110 dilution G for 22 minutes, agitation: 2 inversions every 30 seconds ROLLEI PAN 25 @ EI 25; developed in HC-110 dilution G for 22 minutes, agitation: 2 inversions every 30 seconds

The fog isolated the trees completely from the background and made the trees appear like ballet dancers.

I shot this on Rollei PAN 25 film, I have no idea if this film is identical to ADOX PAN 25 film. I always assumed so but the Rollei film curled a lot more than the ADOX film so I have my doubts now.

I did get a better exposure now that I’m using my Seconic L-758D meter (spotmetered) instead of the Seconic L-308S Flashmate that I used last time. The TTL meter was suggesting all kinds of under- or overexposures so using that would have been useless in this situation.

Water towers of Luxembourg

Sort of a new project for me, the different water tower designs here in Luxembourg. Shot on my Cambo SC2 4×5 Monorail Large Format camera with Rodenstock 150mm f5.6 Sironar N lens, a combination I really start to like.

Photo-2015-08-02-0001-stitched Photo-2015-08-02-0003-stitched

The water tower on the left is on my way to work and I have had now several weeks to see what light would work best. A sunny early morning seemed the best and that is what I went for: the light would not be too contrasty yet and the sun would still touch the tower horizontally without throwing a shadow downward. The light-play makes these photos interesting.
I spotted the water tower on the right on Google maps and will try this one again after the corn has been harvested so I can get a little further into the field to avoid the narrow crop.

ADOX CHS 100 II reciprocity failure information

Now that ADOX CHS 100 II film is available on 120 format (as well as on 135 format and many, many different sizes of sheet film) it is getting really interesting. I have used a lot of ADOX CHS 100 ART on 120 format and loved the results and ADOX CHS 100 II film is said to be just as good. As a medium and large format shooter, I’m really happy that this film is now available in all formats.
ADOX provided a technical sheet for this film here, but crucially, the reciprocity failure correction information was missing. I emailed them, and they kindly obliged and provided me with the following information. I have not been able to verify any of this, I hope that you can let me know how you got on with the information below; it will certainly be a good start:

Up to 1 second, no correction required.
2 seconds: 1.5x (3 seconds)
4 seconds: 2x ( 8 seconds)
8 seconds: 2.5x (20 seconds)
15 seconds: 3x (45 seconds)
30 seconds: 4x (120 seconds)
60 seconds: 6.5x (6 minutes 30 seconds

In a graph it looks like follows (time metered on the horizontal axis versus the required exposure time on the vertical axis):


See also Howard Bond’s article on reciprocity departure for a really good article on the subject which is also referred to as the Schwarzschild effect.

Scanning Large Format

I really need a better scanner that can handle the large format 4×5 inch negatives that I’m working with now, but at the moment I have no choice but to use my Epson V500 PHOTO.

For the moment I found the following solution: I scan the negative in parts and use the Photomerge feature in an old version of Adobe Photoshop Elements to stitch the parts back together.  Not a great way, probably not recommended, but so far it has done the trick. 🙂

Update: I’ve now obtained an Epson V800 PHOTO scanner and get much better results.

Cambo SC2 4×5 camera

I bought a second-hand Cambo SC2 4×5 large format camera, see here for an image of one just like it, and a Rodenstock Sironar APO N 150mm lens, see here. The 150mm lens is on the 4” x 5” negative format similar to a 50mm lens on an 35mm SLR.

This is my first photo taken with this camera and lens combination:

Not an overly interesting scene but important to me in any case as everything worked out. Large Format photography is quite different from using an SLR or a medium format camera: so many things can be adjusted. In this shot the camera is facing down a bit and I tilted the lens even more forward to increase the DOF. The back of the camera is kept vertically so the vertical lines wouldn’t fall ‘backwards.’
The image is composed on the ground glass with the aperture open using the dark cloth to actually be able to make out the details. When you’re happy, you close the aperture, meter the scene and set the exposure on the lens, insert the film holder, cock the shutter, remove the dark slide, release the shutter, reinsert the dark slide, preferably with the black side in front to signal that this side has been exposed and remove the film holder. That’s one photo done!

I posted it on Facebook and a bloke immediately jumped to the conclusion that the white reflections on the water was dust and treated me like a film newbie. So cute when that happens. 🙂