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Showing posts with label light meter. Show all posts
Showing posts with label light meter. Show all posts

Sunday 25 January 2015

Light metering?

For years I wanted to obtain a Bronica and when I did it was a very happy day. The SQAi has done a lot of travelling over the years; in all sorts of weather and across many different terrains. It has let me down on a couple of occasions but I do not blame the camera, overall it has been a great bit of kit. It can be a pain literally on long treks as it is no light weight, even in its lightest configuration.

I have not always been happy with the camera. When I first had it I could not get used to the back to front image which was really frustrating at times. I was not happy with having to use a hand held light meter either. I know! why did I
purchase it in the first place? Boyhood dream of some day of owning one? It has taken sometime for its use to become second nature, but now that it has, my picture making has become more fluent.

Along the way, my light meter use has changed; with some experimenting, I have found that two readings is better than one over all, making white bland skies with monochrome film a thing of the past. I, like you, have tried to solve it by using black and white filters from yellow to red and graduated neutral density filters to name a few. All of which are now gathering dust some where. Really and truly all you need to do is take a second light reading. Of what? The brightest part of the scene which in most cases is the sky and the amount of time it takes to do this makes it a no brainer. In fact you could have taken several in the time it takes to read this.


An understanding of Ansel Adams zone system helps to produce better negatives.

The picture right give a rough idea on how it works.

I have metered skies that have been as much as six stops brighter. In these cases, would it mean shutting the lens down by three stops to allow for it? With a little bit of help from the zone system you may only need to allow one stop to improve the detail in the sky, this would lead to better detailed negatives. The extra information would lead to more easily produced photographs.

Yes you can bracket your exposures which is a good way of learning what works best for you but as a long term method it is a waste of film. The idea is to know what works so you can get it right first time.


On average I have found that the skies in my pictures are about two to three F numbers brighter, meaning a slight adjustment to the exposure before pressing the shutter will produce more detail in the sky on the processed negative, without making the main part of the image too dark. When it comes to printing, whether burning in or holding back, depends on which method you prefer to use in the darkroom. My working method leads me to add light (burn in) more often than take it away (hold back). The sky is not always the brightest part of the picture, I'm using it in this case because it is the most common complaint with developed negatives and to keep my explanation simple.

The following pictures show what happen when the sky is taken into account:


120 format Film FP4+, 6x6 negative,
 Developed in ID11 ,
Printed on Ilford multigrade RC gloss,
 Developed in Ilford multigrade.





This picture was metered for the piper. I did not take a second reading for the sky. I have been unable to burn the sky in hence the white out so to speak.















120 format film FP4+, 125 ISO, 6x6 negative
Developed in Ilford multigrade developer
printed on multigrade RC gloss.





With this picture I closed the aperture down by one F number to allow for the sky. For example from F.8 to F.11. As you can see the clouds have been picked out. With a bit of burning in (adding light) The sky would have more contrast therefore stand out.














120 format Fomapan 100 ISO, 6x6 negative,
Developed in RO9, Printed on Ilford multigrade RC
gloss, Developed in Moersch 6 Blue.


This is a badly scanned photograph but it does illustrate how well the clouds stand out.

It was a difficult scene to meter. The lighting was changing quickly. The light reading for the sky was indicating a difference of three F numbers in brightness more than the overall reading.  In the end I only shut the lens down by one F number. It is a straight print without any burning in.











Saturday 9 June 2012

Light meter.


The weather has been great this past week and not one to pass up such a rare opportunity I have moved my office to the end of the garden where it is shaded  by some silver birch trees. If it was not for the shade I would not be able to see the computer screen.


As you know from previous posts I have become quite smitten with my Zero 6x9 deluxe camera. It's lack of through the lens metering! Your right no lens, I have had to revert to using a hand held one. NO! I'm not going to take another camera with TTL with me. Why load myself down, believe it or not even with a tripod it is lighter than my standard kit. Besides I don't need the light readings to be that spot on especially when needing to account for reciprocity.


While writing this I'm joined by a baby starling. It looks like the one I saved from the jaws of the cat the other day. The bird seems happy for me to be here as he/she walks up to and around the chair I'm sitting in looking for local delicacies. It appears I'm the last thing it needs to worry about.


Two types of hand held light meter
I have two types of meter to choose from they are tried and trusted run of the mill units. The oldest one uses a selenium cell which is a type of photovoltaic / solar cell. When the front of the meter is exposed to the light it produces a small current which moves a needle that indicates how much light there is. This type of meter is batteryless but one of the down sides is in low light situation it requires a certain light level to read accurately.


The other light meter is a CdS unit or Cadmium Sulfide cell that has a greater low light sensitivity. This light meter works by regulating the energy in the battery rather than producing a current as in the former. With this type of meter it can suffer from drifting this is where the meter has been shown a bright light temporarily making it blind. The cell has a memory and can fool you into thinking the level of light has not changed. It is a good idea to let the meter read the scene for several seconds to make sure it has read it properly.


Note the starling casting a
critical eye over the
photographs.
Todays meters do not suffer from this they use silicon blue or gallium arsenide photocell coupled to a memory chip  so are unlikely to have a time lag in changing light conditions.

My light meters are general purpose, they read reflective light from a fairly large area of the subject which is about 30 degrees. They round this reading to an average of 18% ( a mid grey) no matter how dark or bright the scene is. This is where the zone system ( See Ansel Adams The Negative for more info) comes into its own or a system of your own to allow for it. I have my own method that works well with a little bit of intuition thrown in. Well! Most of the time.

Since writing this my CdS light meter has passed away. It will be missed.