Analogue Photography - Methods of Exposing

[Rob MacKillop]

Spent the last hour looking at the beautifully exposed photos of Edward Weston, Paul Strand and Ansel Adams, and being left with the not very nice feeling in my gut that I really don't know what I'm doing - and that I'd like to change that.

When shooting analogue, I always opt for auto exposure when available. My experience with medium format and manual exposure left an impression on me that it is hard to get exposure just right, in fact I very often got it very wrong. I used an old exposure meter and/or an exposure app on my phone - both were often in disagreement. So, auto exposure it is...

But I feel I'd like to refine AE to suit my aesthetic preferences, which means overriding it. I'm not mathematically gifted, so complex equations won't help at all. I don't really understand the zone system either. Part of me, the negative part, thinks I'm too damned stupid to understand what I should be doing to achieve the best exposure. Part of me thinks I'm stupid for thinking that...

Here's a badly-exposed shot I did recently, using the Hexar and XP2:



I just focussed on the brickwork with a half-pressed shutter, then recomposed. F5.6, if I remember correctly. The sky is overblown, and the path/wall in the foreground is somewhat disappointing. I remember definitely wanting the curve of that small wall in the frame, as it provides some continuity to the shadow on the brickwork under the bridge.

I feel a knowledge of the zone system would have helped here. What should I have done? Take a reading of the sky, the bridge, the path, then somehow work out an average exposure? Wouldn't that just render a flat image?

Your advice appreciated...

Nik Silver version: It has more definition to the trees beneath the brickwork, but has lost any detail of the path. The sky has a bit of grain, but hasn't improved much.

 

[Rob MacKillop]

The Hexar is well capable of calculating a good exposure under the right conditions:



I love the blacks of the guy reading the paper. Those deep blacks seem to allow all the shades of grey (at least 50!) to be present. But this is a well-lit scene from above - note the near absence of shadows.

I never get this quality of exposure when outside.

 

[Rob MacKillop]

Looking at the first image again:



The Zone System, as I understand it, would have the darkest area, the path and small wall, as Zone III (some detail). Mid-range is Zone 5 (what light meters read), therefore I should have lowered the f-stop of 5.6 by two places, which on the Hexar is 2.8. But other cameras have other f-stops, so where exactly is two stops below 5.6?

Is this the correct use of the zone system?

 

[Hamish Gill]

Two stops from 5.6 is 2.8 with 4 in between. The other numbers you see on some cameras are fractions, usually 3rds or 1/2 stops.
A good place to start would be understanding the reciprocal relationship between aperture stops and shutter speed ... Though you light know that already??

If you exposed the area of the photo you have picked as zone 3 as your zone 5 you would end up exposing very much to the right and the photo would look very bright. If you were looking at that scene and you wanted to expose that area for zone 3 you would take a reading off it then -2ev

So if you had a reading of 1/250th and 5.6 off that wall, you would shoot at 1/1000th and 5.6 to put it into zone 3

1/250th and f11 would also give you the same exposure since the difference between 5.6 and f11 is 2 stops and the difference between 1/250th and 1/1000th is 2 stops.

I'm never t sure where you are up to already, so in not 100% how to best approach helping?

 

[Rob MacKillop]

Later...rushing off to Dundee. Back this evening.

 

[Rob MacKillop]

There must be a table of reciprocal readings between f stops and light readings?

 

[Hamish Gill]

There isn't a table, the difference between 1 stop and another is just always the same

2.8 - 4 halves the light
1/100th - 1/200th halves
100iso - 200iso doubles

4 - 2.8 doubles
1/200 - 1/100
200iso to 100iso doubles

Shutter and ISO are easy since its just basic maths.
Divide the number by 2 to get 1 stop increase, times by 2 to get 1 stop decrease

Admittedly it does get a bit confusing that it goes 1/8th - 1/15th in shutter speeds, but if you just accept that the numbers are rounded in places, for the most part it's easy

Apertures are harder since the maths is based on a circular aperture and if you remember circles in maths at school you will remember the confusion.

The reason it is more difficult is actually there so as to make it more easy. The f numbers are to make uniform what would otherwise be quite confusing.

So, a 50mm f/2 lens, (where 'f' is focal length) has a maximum aperture of 25mm. 50/2 = 25
A 100mm f/2 lens has a maximum aperture of 50mm . 100/2 = 50mm.
They are both f2 and therefore (in theory) let the same amount of light in, yet the 100mm lens, because it is a longer focal length needs a much bigger aperture (hole) to let the same amount of light in.

In short, since apertures are variable because of focal length, there needs to be a system to represent aperture to bring them all together for the sake of easy (easier) understanding.

The best thing to do with aperture is to try to remember the standard 1 stop scale
f/64, f/32, f/22, f/16, f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0,/f1.4,f/1

From one to the next in that scale the hole is literally twice as big, it therefore doubles the amount of light. or reading right to left halves the amount of light. The number in between these, as I said above either are sometimes confusing since they are sometimes 1/2 stops and sometimes 3rd stops. but if know the full stop numbers its usually easy enough to work out.

The point is, that all the different methods of exposure: shutter speed, aperture and iso all have 1 stop scales that either half or double exposure. Aperture by the size of the hole, shutter speed by the amount of time, and iso by how sensitive the film/sensor is.

What this allows, and this is the important bit, is for us as photographers to retain the same exposure but have different camera settings depending on our priority.

For sport we might prioritise a fast shutter speed, for landscape we might use a smaller aperture (to give more depth of field), for portraits we might use a wider aperture to give narrow depth of field to isolate the subject. But all of those situations might be in exactly the same level of light. So to allow us to prioritise one setting, we have the others to compensate.

Light is represented in 'EV' or exposure value (read some of this - http://en.wikipedia.org/wiki/Exposure_value)

So today looking out my front window its a grey day I have EV13 (100iso)



this gives fairly average settings of 1/1000 5.6 400 iso - this is fine for snaps and what most cameras would select on program AE



if I wanted to shoot sport Id be happy with the fast shutter speed but might want a bit more dof to help me get focus on a fast moving subject. By adjusting the aperture by 1 stop from 5.6 to 8 to increase dof, I decrease the amount of light hitting the sensor by half. So to retain the same exposure I can increase the iso by 1 stop from 400 to 800 thus doubling the sensitivity.



if I wanted to take a portrait I might want to drop the background to out of focus. so I choose 1.4.
1.4 is 4 full stops from my original reading of 5.6. So to compensate and get the same exposure I need to adjust other settings accordingly.
In this instance I have adjusted the shutter by 2 stops 1/1000 - (1 stop) 1/2000 - (2 stops) 1/4000
And the iso by two stops 400iso - (1 stop) 200 iso - (2 stops) 100iso
I could have also used 400iso and 1/16000 shutter, or 25iso and 1000th but my camera might not have those settings ... you get the point I hope

another example would be for landscape



f/16 for broad depth of field. f16 is 3 stops from 5.6. But I also want to keep my iso low for noise/grain free image. 100iso is 2 stops from 400iso. 3+2 is 5 so since we have a preference for both aperture and iso we need to adjust our shutter speed by 5 stops.
1000th -(1) 50oth -(2) 250th -(3) 125th -(4) 60th -(5) 30th

This is reciprocity in action
Get your head round this and all of a sudden the zone system will make a hell of a lot more sense... I wouldnt go near the zone system with a barge pole until all of the above comes as naturally as breathing... to make it come naturally I would by a very old fully manual camera and a simple light meter

Does that help?

 

[Rob MacKillop]

Back home earlier than I thought, and I had time to read and contemplate that brilliant post, Hamish, for which many thanks are due.

Right, I understand the relationship between light and f-stops, and I have already become familiar with using a light meter for medium-format work. I also have a rough grasp of the less accurate, but sometimes useful, Sunny 16 rule.

So I'm back again contemplating the zone system for high-contrast shots, such as the one I featured at the start. Different areas of the scene will give different readings. The question is: How to combine them? Did you cover this, Hamish, and I just don't get it?

PS The F4 body arrived - what a tank! I love it. And it looks to be in mint condition. What a bargain. I'll be in touch regarding one of your lenses. I didn't expect it to arrive for another two weeks, but here it is. Definitely a different world of photography than I'm used to, which is what I wanted - I'll enjoy learning about how to get the best out of such a camera and its lenses.

PPS Batteries also arrived for the £3.99 Pentax Zoom 90!

What a day...

 

[Hamish Gill]

You aren't so much combining them using the zone system, more choosing exposure based on the area of shadow you want detail. So, referring to my pervious comment, if the wall is the area you want detail you would put that in zone iii. To do so, you take a reading from it with a spot meter or close up, then take off 2-3ev.

The problem with using the zone system for both shadow and highlight from your perspective is that it requires you to develop your own film. Since to control the highlights of a high contrast scene, you need to cut the development time, thus lowering the contrast.

This is what's called "exposing for the shadows and developing for highlights" (a Google search of that will send you down a rabbit hole - be warned )... It also takes experimentation to get right.

I've actually never done it, though I have tinkered with exposure vs dev time to some effect, I've only done it to increase contrast.

 

[Hamish Gill]

Good news about the f4 and batteries ... Email response on the way

 

[Rob MacKillop]

Ah, OK. Rabbit holes and brick walls - I'm alerted!

 

[Hamish Gill]

good luck searching... if you discover anything good, id be interested!

 

[Brian Moore]

I really don't know what I'm doing

Welcome to where I am.

Excellent responses @Hamish Gill. Thanks.

 

[Martin Pancisin]

Thanks for your explanation @Hamish Gill, this is most useful!

 

[Martin Pancisin]

So I'm back again contemplating the zone system for high-contrast shots, such as the one I featured at the start. Different areas of the scene will give different readings. The question is: How to combine them? Did you cover this, Hamish, and I just don't get it?

@Rob MacKillop do you have Ansel's - The Negative (starting page 53)? There is an example which gives an answer to your question. If not I can help you, just let me know

 

[Rob MacKillop]

I do - I knew there must be a reason why I bought it! Thanks, Martin.

 

[Julian de'Courcy]

The Hexar is well capable of calculating a good exposure under the right conditions:

View attachment 10114

I love the blacks of the guy reading the paper. Those deep blacks seem to allow all the shades of grey (at least 50!) to be present. But this is a well-lit scene from above - note the near absence of shadows.

I never get this quality of exposure when outside.

Rob I aught not to contribute, although I know what Hamish is saying I do not have anywhere the expertise to explain it.Although spent many months as kid in a dark room chasing rabbits down their holes, for that perfection. I say aught not to contribute as I am probably saying something you know I am sure, except reading this snip of the post pulled me in and wondered.

You mention here the 'Right conditions' and not getting the exposure as well as outside shots. That is to do with the dynamic range and the inability of the film or sensor in it's ability to capture it all, not the inability to know how to expose correctly. But knowing how to expose purposefully you can choose what part to expose correctly when the dynamic range is to large and also jiggle it a bit in the development.

I am always bold over when shooting in that golden hour, morning or evening when the even exposure and the highlights and shadows are captured . So much easier to shoot in those hours or in controlled studio light purely because the dynamic range.



Hope I am not barking up the wrong tree here. Apologies if I am.

 

[Rob MacKillop]

Not at all. I always welcome your thoughts. It's 7.20am here, and I should be out with my camera, not sitting at a desk writing. In ha;f an hour the Golden Hour will be over. Maybe I'll catch this evening's? You are right about the quality of light at different times of day, and the camera's ability to cope with it. "Purposefully" is a better word than "correct", for sure.

Thanks, Julian.

 

[Hamish Gill]

I think Julian's answer is better than mine. As I said in my post, I've never pursued the route I explain ... Though I might with larger formats. For 35mm the joy is in the moment, if the dynamic range is too great, it's too great, work with it, capture your subject and so what about the consequences?! The key really is just knowing when it is going to happen, being able to judge the light, if for no other reason than simply avoiding being disappointed when you have lost detail in the sky/highlights or shadows.
At least it is film you are talking about, film always feels more forgiving when it comes to these things

 

[Rob MacKillop]

True.

Thanks, gentlemen. Much to mull over, as usual.