Tech Talk – Testing exposure with a gray scale

The shooting

I took a gray scale and color control patches, a medium format camera, a roll of Ilford HP5+ and a standard light meter. The metering was done close to the target and in reflective mode. The light outside was flat and very even. I shot the metered value first, then -2 stops, -1stop, followed by +2 stops and finally +1 stop.

The developing, scanning and editing

The film was developed in the standard developer Tetenal Ultrafin at 20C for 13min. In general the film looked Ok and well balanced. I used a Canon 9000F and Vuescan and didn’t chop off any levels. In Adobe LR4 I moved average gray to 50%, white to about 2-4% and black to 96-98%.

The results

Here is the first image at meter reading. There is very good separation in the lights. However, the shadows especially between patches 18 and 19 are difficult to differentiate.


The next images shows the results with 2 stops underexposure. There is no problem with the separation of the highlights as well as in the previous exposure. The patches 17 -19 all fall together and there won’t be any detail in the shadows anymore. The shadows are simply underexposed. It also seems that the grain is more visible since there is more stress on it in post-processing.


Best shadow detail and separation is achieved with overexposure. The sample exposed with +2 stops shows a clear difference between patches 17,18 and 19 while the highlights are still not totally blown out.


The conclusion

We were taught by Ansel Adams to expose for the shadows and I think this still holds up today. The question is should we really develop for the highlights? If the plan is to scan the film after developing it, you don’t need to care too much about your highlights since the digitalization process got enough latitude for lights and has its weakness in the shadows.

I realize this is not a scientific assessment with an exact analysis of numbers and levels. Yet, it gives you a hint what to take care of first and that is: shadows. If you don’t expose for the shadows, detail there will be lost and nothing will get it back onto your film. In general I think it is better to overexpose your film slightly and avoid underexposure.

Camera Talk -The Pentax 645N

Back in 2002, I got my first Pentax 645NII. Even though digital photography was certainly winning more and more ground, I decided to give it a shot. I was shooting mostly color slides and a bit of b&w film back than and I just recently sold a Contax G2 to get my first digital SLR, a Fujifilm S2.

I think I used the camera for about a year on trips to Cambodia, Japan, Germany, China and in Taiwan where I recited at the time. I even have some framed prints left from these rolls but mostly scanned the slides which are sitting somewhere on my hard disk now.

I sold the piece at the B&H store in New York and got a Voigtlaender Bessa R.

Just a year ago when still living in Singapore, I saw a good deal for a Pentax 645N with a 45-85mm, 1:4.5 lens on ebay. I got it even though my memories were mixed.

First of all that thing is heavy. It ways about 2kg with lens and still 1.2kg without. It’s a real pain to haul around. Yet, it works like a 35mm SLR. The autofocus is fast and reliable. The camera got spot, center weighted and matrix exposure measurement and you can adjust the exposure by +/-3 stops in 1/3 steps. You even can bracket your shots. Maybe someone uses it for “film” HDR. But it did come handy when shooting slides.

Here are a couple of slides I shot 2003 in Cambodia

The Pentax 645N was released in 1997. Autofocus was added to the 645 and a new series of autofocus lenses was released as well. It seems to me that the 45-85mm zoom lens I got isn’t the sharpest. I was looking around online but only found good reviews. I guess it doesn’t help to scan and zoom in to 200%. It is film after all.

Apparently, the 645 series was developed for amateur wedding photographers. Today, the camera is bargain for landscape and fine art photography. Even though, Hasselblad and Mamiya 7 lenses are going to beat the Pentax lenses but what you get is more speed and fun shooting.

Here are a couple of images I shot recently on Ilford FP4+ and HP5+:

Ilford HP5+ developed in Spuersinn HCD

Ilford FP4+ developed in SPUR Acurol

Ilford HP5+ developed Spuersinn HCD