Investing in a Sekonic

[pentaxuser]

The irony for the OP is that if low light photography is his main interest and this involves, as it does reciprocity problems and he knew his app does a good job in respect or recording low light then any trad meter's chance of giving him a real edge compared to the app was always remote. Once you are into long exposures of many seconds does it matter if one meter is slightly better than another. If I arrive at a time of 85 secs based on a phone app and reciprocity tables and you arrive at 88 secs based on a good analogue meter and the same tables how much difference will there be in the negative?

Not a lot I'd have thought.

pentaxuser

 

[MattKing]

Long exposure work and incident light meters seem perfect for each other.

 

[RalphLambrecht]

+1

 

[LMNOP]

Okay, I'll try.

When you expose film in "normal" circumstances, there is a reciprocal relationship between the intensity of the light reaching the film (determined by the ambient light intensity, and the aperture set on the lens) and the length of the exposure (shutter speed).

If the aperture is adjusted by one stop, you can get the same result by changing the length of the exposure by the reciprocal of one stop.

Same for adjustments of two, three, four or more stops.

In other words, reciprocity of light intensity and exposure is maintained.

However, if you start working outside of the "normal" range, the reciprocity starts to fail.

What constitutes the "normal" range will vary a bit between films.

When the light is so dim that the necessary reciprocal exposure time is very long - lets use two minutes as an example - the film responds less than when you are working within the normal range, so you need to add more light to the film to get the same result. You can do that by either changing (increasing) the ambient light, changing the aperture, or by increasing the exposure time even more. The guides to how much you need to increase the exposure time are a bit imprecise, because this varies with light conditions (contrasty vs not), subject brightness range and film type. Basically, you use the guides, you bracket, and you apply experience as you acquire it.

Just to be clear, although we tend to think of reciprocity failure as being linked to longer exposures, it is actually caused by the low level of light that necessitates those long exposures.

You may also encounter reciprocity failure with extremely short exposures (usually when using electronic flash at the boundaries of their appropriate operation) but I wouldn't worry about that for now.

this is a huge help! Thank you.

I I have a lot more reading to do, but more importantly, I am forcing myself to get out and shoot as much as possible. This weekend I was using my iPhone app for some night photos, mostly just a few seconds for exposures, but I will learn from experience. Frankly, I've been doing this more than the post leads on, but I am looking to improve my metering abilities and get even better results. Usually I get some idea from the meter and my gut will do the rest. I love reading this stuff, it's great. I was just out walking on a beautiful sunny Easter, shooting some black and white. If it's not too cold I'll be doing night stuff later on, and tomorrow I pick up a roll with some night work, I'll share the results!

 

[LMNOP]

Long exposure work and incident light meters seem perfect for each other.

How so? I am confused as to how to use this thing at night. For instance, I am trying to capture a corner store late at night, the neon sign and all the windows are glowing out onto the pavement, no streetlights, and a window is on in the apartment above. My iPhone gives me a real preview of what that image should look like, and I usually add some time to the recommended exposure. This shot happened to come out perfectly, I just got the negs back, but I used my iPhone, because I am not sure how this meter would read that scene, given the extremes.

 

[baachitraka]

Incident reading will give you an amount of light falling on the subject.

Typically during night, its the darkest part of the subject that need to be metered to ensure that there are some details on the negative.

Incident meter does not see the nature of the light, it just measure the amount of light falling on the subject.

 

[craigclu]

I'd like to put in a plug for the Sekonic L-718. Very durable, accurate and has many useful accessories (5º Spot, ground glass reader, dome selection, reflection capability). It's capable of multi-flash (cumulative), uses AA's and has a memory feature for zone spreads, etc. Attached is a quick guide that outlines most of its features. I also have the L-398 and if you don't need extreme low light use or flash readings, it will serve you very well (I have the slide set and it can be useful).

 

[sagai]

I have the lightmeter app on android, proven to be accurate for my purposes.

 

[John Koehrer]

How so? I am confused as to how to use this thing at night. For instance, I am trying to capture a corner store late at night, the neon sign and all the windows are glowing out onto the pavement, no streetlights, and a window is on in the apartment above. My iPhone gives me a real preview of what that image should look like, and I usually add some time to the recommended exposure. This shot happened to come out perfectly, I just got the negs back, but I used my iPhone, because I am not sure how this meter would read that scene, given the extremes.

In this situation using an incident meter would just blow out the interior etc. etc. It MAY have given a decent exposure for the
exterior. Maybe! How low a light will the meter read? Would using the incident ball reduce that sensitivity?

If you're comparing the app to the meter though, that would have been a good time to make an exposure with each
one and compare the negatives.

 

[pentaxuser]

Surely as John Koehrer says an incident meter would be completely fooled in the shot LMNOP describes. It has to be a reflection meter and if you are shooting into the store's window then I'd have thought that any reasonably accurate meter would give a good reading and unless you have used a very small aperture the reading is unlikely to get into the realms of reciprocity failure unless the film has a particularly poor record on this front.

If the app does the job that is required then that's good enough isn't it?

All I would add is that if the exposures can stray into several seconds look for a film that requires little or no compensation to be added under 5-10 secs or a very fast film such as D3200 that is unlikely to get you into that territory

If fine grain and full of sharp detail is required then a monopod or even tripod may be required in which case switch to Fuji Acros where reciprocity failure only starts at about 120 secs

Such a shot of the scene described will be contrasty of course with little but blackness outside of the shop's window but if you do not want to "blow out" the window and it is the main or only lit part of the scene then I can't think of a way round this.

pentaxuser

 

[MattKing]

How so? I am confused as to how to use this thing at night. For instance, I am trying to capture a corner store late at night, the neon sign and all the windows are glowing out onto the pavement, no streetlights, and a window is on in the apartment above. My iPhone gives me a real preview of what that image should look like, and I usually add some time to the recommended exposure. This shot happened to come out perfectly, I just got the negs back, but I used my iPhone, because I am not sure how this meter would read that scene, given the extremes.

I wouldn't consider this example a "long exposure" situation. For this situation, a small degree spot meter is about the only tool that will be particularly suited.

Essentially you are photographing light sources themselves, rather than what they are illuminating. No light meter is designed with that situation in mind.

A moonlit ocean scene is a long exposure situation.