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How to light measure
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PostPosted: Sun May 25, 2014 8:45 pm    Post subject: How to light measure Reply with quote

Hi all,
I find my self shooting more and more in cases where the multi measuring of my minolta does not help at all..so I though to explain some of the hard cases and help me find the solution on how to measure those

1. I paint a wall white and one if the corners I put a nice red cross which might make a nice color-contrasty composition (negative space too). If I meter a surface there is just white I will get grey colors instead of white. So how much I need to overexposure to get real white? Will that then be adequate for whole scene (not just the white wall but the red cross in it)

2. One think that always bother me is how to get close to what my eyes see. Okay this can be very subjective what one means close, but I guess we can assume here that a night shot should be night and not an overexposure that will render the environment dusk (few hours before sun leaving horizon). The other time I got in the kitchen and I saw very little light behind my curtains and I find my self "ok lets try something similar, capture the light that gets inside and keep the room poorly lit). How I am gonna measure for this kind of shot? How I can try to think reducing the gap between light metering (and this grey assumption) and how I see the environment?

I would like to thank you in advance for your reply
Regards
Alex


PostPosted: Sun May 25, 2014 11:01 pm    Post subject: Reply with quote

...you can't trust your eyes to represent a camera (well maybe if you are experienced) as your iris automatically adjusts to the light from darkness to brightness. The camera on semi auto can usually give you a decent shot, but as you know can be fooled and all you have to remember is the camera meter tries to average everything equivalent to approximately a Kodak grey card (some argument whether Kodak grey card is the standard or camera manufacturers decided their own, anyway it would be near).
Well most things (to the camera) in the same light are roughly near the grey card which on general subjects gives a nice shot and the film's latitude compensates for errors as well, but a white wall or black cat are way out, so you have to correct the camera.


PostPosted: Mon May 26, 2014 1:52 pm    Post subject: Reply with quote

Excalibur wrote:
...but a white wall or black cat are way out, so you have to correct the camera.


hi,
I am trying to understand though the how. So back to the white wall with the red cross in a part of it. I can turn my camera and fill the frame only with the white.. my camera gives me a X exposure suggestion. What I do next? How I can calculate the "difference" between my white wall and the greyish surface my camera tries to measure?

Alex


PostPosted: Mon May 26, 2014 6:30 pm    Post subject: Reply with quote

alaios wrote:
Excalibur wrote:
...but a white wall or black cat are way out, so you have to correct the camera.


hi,
I am trying to understand though the how. So back to the white wall with the red cross in a part of it. I can turn my camera and fill the frame only with the white.. my camera gives me a X exposure suggestion. What I do next? How I can calculate the "difference" between my white wall and the greyish surface my camera tries to measure?

Alex


Well you have picked one of the worst cases to photograph esp if the white wall is shiny and reflecting sunlight Shocked Anyway you have to decide what is more important to you i.e. detail in the white wall or say a pattern in the red cross...but film would probably just have the latitude from white to red (but not black to white) at the same time. So as mentioned in other threads take an incident light reading or reflective reading of something equivalent to a grey card e.g. blue sky or light green grass or light grey pavement and take one shot for this reading and a second with the lens opened by one stop (just in case of exposure errors). But remember the reflective equivalent of the grey card has to be in the same light as your wall shot.
Some people with a spotmeter would take a reading from the white wall and a reading of the red cross and choose a reading in the middle to set the lens aperture h'mm and hope for the best Wink


PostPosted: Mon May 26, 2014 8:00 pm    Post subject: Reply with quote

Excalibur wrote:


...Some people with a spotmeter would take a reading from the white wall and a reading of the red cross and choose a reading in the middle to set the lens aperture h'mm and hope for the best Wink

thanks for the answer. I also guess that film should be able to handle both. So I then need a light meter. Which one? What I measure and how I calculate the right exposure based on the reading of my external meter?
Where I can read about this stuff

Regards
Alex


PostPosted: Mon May 26, 2014 8:16 pm    Post subject: Reply with quote

alaios wrote:
Excalibur wrote:


...Some people with a spotmeter would take a reading from the white wall and a reading of the red cross and choose a reading in the middle to set the lens aperture h'mm and hope for the best Wink

thanks for the answer. I also guess that film should be able to handle both. So I then need a light meter. Which one? What I measure and how I calculate the right exposure based on the reading of my external meter?
Where I can read about this stuff

Regards
Alex


Well unless you have loads of money then you should only buy what you need, and if I can get by without a separate exposure meter then so can you. Mind you I sometimes use a camera with no built in meter, but as I always carry two cameras around so there is no problem.
Anyway sunny 16, incident light reading, reflective reading from a grey card are all the same IF everything is in the same light.

There are many books on exposure and how to use light, but haven't read any for years but then I admit to only being just a competent photographer for the limited type of shots I take and am pleased what I do and don't mind if no one else likes my shots. Wink


PostPosted: Mon May 26, 2014 8:56 pm    Post subject: Reply with quote

The built in meter or a separate meter will tell you the same. The camera is trying to average out the scene to a 15% grey. When doing weddings I had a similar problem as the brides dress would fool the meter into underexposing. This is what the +/- dial is for on your X700. For this extreme subject I think +1 would do it for you. Photographing dark subjects will have a similar result, they end up too light.

Try shooting it with a digital camera and increment the exposure in +0.3 or +0.5 steps.

Experience is what you need - not a meter.

We really had to wing it in the old days and it took years to learn.


PostPosted: Tue May 27, 2014 6:51 am    Post subject: Reply with quote

Edited

Last edited by bernhardas on Sat Apr 02, 2016 7:32 am; edited 1 time in total


PostPosted: Tue May 27, 2014 6:56 am    Post subject: Reply with quote

Edited

Last edited by bernhardas on Sat Apr 02, 2016 7:32 am; edited 1 time in total


PostPosted: Tue May 27, 2014 10:09 pm    Post subject: Reply with quote

Thanks a lot for the very good feedback.
Here is my comments.
-Yes I am intresting in more deep understanding. Perhaps this is one of the reasons I have felt so much in love with the film that makes me slow down and start from scratch.
-I was reading the other time this website, that I have to admit that is very nice for black and white photography
http://www.rogerandfrances.com/subscription/choosing%20bw%20films.html
there they have been mentioning that the grey card is not always the safe bet. Your darketst shadow might be many stops away from the grey tone. They were explaining that I need to measure the darkest tone I need still details to appear and for the highlights change the development time.

It is not clear though
a. which tool to buy to start doing the measurements? Spot meters are more precise to get a value to use directly where incident light meters they still do averaging and they always need a bit of "translation
b. what these meters provide you? Specific camera settings? How based on the darkest tone and the lightest tone you find the best exposure?

Still these things baffle me

Regards
Alex


PostPosted: Tue May 27, 2014 10:50 pm    Post subject: Reply with quote

From the article:-

****don't panic

It is possible to worry much more about lighting than you need too: after all, it is only when subjects get really tricky that serious, heavy-duty metering is required. ****

There is nothing wrong with learning to be an expert on exposure esp related to dev and pushing film, but instead on enjoying taking shots, you might as well use a DSLR for all your testing than waste "lovely" film.


PostPosted: Wed May 28, 2014 10:58 am    Post subject: Reply with quote

Edited

Last edited by bernhardas on Sat Apr 02, 2016 7:33 am; edited 1 time in total


PostPosted: Thu Jun 26, 2014 8:34 pm    Post subject: Reply with quote

bernhardas wrote:
P.S. : I f you are serious about Film for some time to come I recommend to buy or borrow (through your UNI Library) the three books from Ansel Adams: The Camera, The Negative, The Positive.

.


any ideas how to put priorities?
any ideas which book to use on how to use a light meter?

Regards
Alex


PostPosted: Thu Jun 26, 2014 9:17 pm    Post subject: Reply with quote

Book: Understanding Exposure


PostPosted: Thu Jun 26, 2014 10:04 pm    Post subject: Reply with quote

One simple thing you could do to start off with is to meter just the subject you want at correct exposure and ignore the rest of the scene.
This means you'd need to get up close to the red cross in your example and meter just that. The same applies, for example, to a skier
against a snowy background or, conversely, a bride in a white dress against a dark wall. In your example, obviously the white wall will
be overexposed, so you have to make a judgement about what you need. After some some practice you will be able to judge the
settings to achieve the exposure you want.


PostPosted: Thu Jun 26, 2014 11:55 pm    Post subject: Reply with quote

alaios wrote:
bernhardas wrote:
P.S. : I f you are serious about Film for some time to come I recommend to buy or borrow (through your UNI Library) the three books from Ansel Adams: The Camera, The Negative, The Positive.

.


any ideas how to put priorities?
any ideas which book to use on how to use a light meter?

Regards


Alex



The Negative. All about Zone System, read it, learn it, apply it and you're done with exposure for the rest of your photographic life.
Actually, the third title is "The Print". I have the 3 titles, bought in the begining of the '80s.

Cheers,

Renato


PostPosted: Sat Jun 28, 2014 7:28 am    Post subject: Reply with quote

You can meter from one spot, and whatever is in that spot is perfectly exposed. What about everything else? It will be incorrectly exposed but the film latitude helps in this case and everything is balanced.

So if if you are relying completely on film latitude to balance up all the other tones, does it really matter that the exposure should be so critical?


PostPosted: Sat Jun 28, 2014 3:25 pm    Post subject: Reply with quote

philslizzy wrote:
You can meter from one spot, and whatever is in that spot is perfectly exposed. What about everything else? It will be incorrectly exposed but the film latitude helps in this case and everything is balanced.

So if if you are relying completely on film latitude to balance up all the other tones, does it really matter that the exposure should be so critical?


Well, no, even spot meters can be fooled...what if the spot chosen is white or black? Wink

Only Incident Light Meter is accurate...


PostPosted: Sat Jun 28, 2014 9:40 pm    Post subject: Reply with quote

I was doing a little more thinking about this....

Back in the old days Ansel Adams and co had systems for the whole process.

1: Select the right film for the job
2: Meter the scene as you prefer it to be done
3: Expose carefully
4: Develop the film with carefully selected/modified chemistry for a certain time to get your perfect neg.

Of course this is only half the story. The negative must be printed too. So you decide:

5: Condenser or diffused illumination.
6: Lens and aperture
7: What type of paper (Ilford make 13 varieties)
8: What grade.
9: Exposure time
10: Dodging, burning
11: Development time
12: Any after process treatment of the print for example toning.

This whole process is what makes a print. scanning after development is just doing half a job. Can it be as good?

So the question is. Will precise metering and careful development actually achieve better results then just using bog standard FP4 in ID11 for the time printed in the leaflet. If its just going to be scanned in probably using a 'Mickey Mouse' scanner?


PostPosted: Sat Jun 28, 2014 10:48 pm    Post subject: Reply with quote

Yes, it will. Properly exposing a film is capture shadow details where you intended to do, and properly developement is capture details in the highlights until the amount you wanted too. A.A. used to say as an adagio: expose to the shadows, develope for the highlights. No scanning procedure can put data in the negative where this data doesn't exist, i mean both shadows and highlights, only correct exposure and development can. This is what A.A. Zone System actually - when correct understood and applied - was conceived to do,

Cheers,

Renato


PostPosted: Sun Jun 29, 2014 9:26 am    Post subject: Reply with quote

I understand your reply and this is pretty much what I was getting at.

My point was that with all that extra info on the film - subtle tone grades etc, is a mickey mouse scanner going to pick up all these nuances of tone accurately? I think not.


PostPosted: Sun Jun 29, 2014 11:51 am    Post subject: Reply with quote

Phils,

Neither me, it's a question of trying to see what one can get. The only think I can know in advance is that bigger the "print", more critical will be the type of scanning.

Cheers,

Renato