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I think I'll never comment on a film speed testing thread again. The whole "my nerdy testing method is better than yours" is completely inconsequential compared to how much a camera's shutter might work differently in bitter winter conditions or if a CLA is overdue.
There is a distinction between film speed and EI. Film speed involves precision testing to determine a numerical value that represents the sensitivity of the film. The other has more to do with how to personally apply the concept of film speed to exposure. Except for the ISO speed standard, all testing methods are concerned with finding an EI. Perhaps the whole point of my argument is that each has it's own purpose and not to confuse the two.
You just provided a great piece of info to the discussion, your knowledge is important here. It is important to consider that stuff.Quote:
Originally Posted by jp498
Example:
Part of the reason that I have basically "fallen back to" using manufacturer's recommendations as a baseline (box speed and normal dilutions, agitation, temperature, and times) is that I know they work and work really well. Similarly classic "point the dome at the camera" incident metering is so reliable that there is essentially no question about whether placement is workable or not.
Those two choices with a reasonable bit of practice to learn and to become even marginally skilled in the mechanics of these tasks ensures "pretty darn good" results that will fall well within a range of where a high quality print can be made from the resulting negative.
Which brings me to your point.
By good results I mean that I can say with confidence that, given my baseline, the resulting films will show faithfully my artistic choices and how well my tools are working. If there is a problem I know where to look, it is either my choices, my inattention, or my tools.
A solid tested baseline gives each of us the ability to trouble shoot easily and share that info with others.
It is important, if anyone is going to use my info as a baseline, to know how it works.
The reason box speed and classic incident metering works just fine for most people, including me, is that it pegs what is typically most important in a shot, like Grand ma and the new baby. The latitude inherent in negative films normally takes care of the edges nicely with room to spare. This systemically works so well that IMO the grand majority of all photographers could do this and never be disappointed with their negatives.
There are ways to tweak this though for the people who want that little bit extra to reach the next level of shadow detail in print or whatever is most important.
One of the reasons shooting at 1/2 box speed is basically irrelevant to me personally is my metering methods. When shadow detail is really important in the shot I simply orient the head of the incident meter to measure, for example, open shade, rather than pointing the meter head at the camera which might make it cross lit. A person using classic "point at the camera orientation" would need to use 1/2 or maybe even 1/4 box speed to get the same reading/exposure placement I get.
The inverse applies also. Where others may shoot at double or quadruple box speed in low light, I may simply orient the meter's head to peg exposure from the light source. Our exposure placement may actually end up the same but the logic used to get there is very different.
Without knowing the mechanics of the system I employ knowing my EI is irrelevant.
Not knowing how your shutter behaves in the cold provides the same problem.
The reason I started down this speed testing path, is I wasn't getting the results I wanted on paper. And that was by shooting at box speed and developing according to the manufacture's directions. I really didn't want to test, but by testing, I'd hoped to arrive at a standardized set of actions, from exposure to print. By standardizing my workflow, my hope was that I could find out where I was going wrong. It could be that shooting at box speed isn't my issue. It could be my metering technique, my developing time, my enlarger, my camera's shutter, etc.
Like many people starting out, I'm clueless. I'm not in a position to critically evaluate testing methods, which there doesn't seem to be a shortage of. :) Some methods use a densitometer, some don't. There's the test for zone I or zone III debate. People recommend changing the shutter only, changing the aperture only, changing ISO only, during the test. Shoot a gray card, shoot a wall, shoot a real scene, shoot a set of props, etc. Test at one stop, 1/2 stop or 1/3rd stop gradations. And so on.......
One of the positive consequences of all this variety, is that it's forced me to continue studying and I'm starting to slowly understand some of this stuff.
In the end, I think we all come up with our own methodology for testing, conscious or not. Repetition, practice, testing, whatever you want to call it, it leads to the same end, our personal understanding.
Everyone who has contributed to this thread has helped me. I'm not just saying that. I've discovered I already have a consistent workflow based on factory recommendations, with the exception of printing. A speed test isn't probably where I need to start. I think the most valuable thing for me at this time would be to find my "maximum black" print time, so I have a baseline in which to evaluate, how my negatives print. I just came to that realization today.
Now having said that, I shot my first rolls of speed test shots yesterday, so I'm going forward with testing anyway. :) I'm sure I'll learn something along the way.
I'll close with a couple reads I found interesting:
On this website http://www.barrythornton.com/ go to "technique guide" and choose "The NoZone System." This seems like a good way for ongoing evaluation and tweaking. If someone sees any glaring holes in this article, please let me know.
And this article, http://www.davidkachel.com/historical/calibrat.htm made me aware of variables I hadn't even considered effecting results.
Thanks everyone for your help!
Kenton,
Glad your getting something out of this.
Refining the print process is quite a process. There are some tools that can really help.
https://www.google.com/search?q=koda...on+print+scale these can be found here on occasion or on eBay.
Similarly https://www.google.com/search?q=beseler+pm2l or similar meters can many times be found for little cost and make printing much easier, once you learn to use it.
I'm curious about this Mark. I've been using T-Max films and following factory recommendations and using an incident meter. I'm not good at evaluating negatives but printing with a #2 filter results in a super contrasty print. I don't think I've ever had an easy to print negative using T-Max, unless it looked very underexposed. So at least with T-Max, what you're recommending isn't working for me. Tri-X OTOH, I've not had as much problems with. Have you shot T-Max without any adjusting from factory recommendations?Quote:
Originally Posted by markbarendt
I'm interested in learning more about incident metering. My interest lies in close up photography, verging on macro at times. Often the shadows on the subject are so small there's no way I can use a spot meter effectively, but the light conditions can very a lot. The basic point at the camera, from the subject I get. But I'm not seeing a lot about incident meter technique. Can you recommend any books on the subject? Have you written any articles on the subject?Quote:
One of the reasons shooting at 1/2 box speed is basically irrelevant to me personally is my metering methods. When shadow detail is really important in the shot I simply orient the head of the incident meter to measure, for example, open shade, rather than pointing the meter head at the camera which might make it cross lit. A person using classic "point at the camera orientation" would need to use 1/2 or maybe even 1/4 box speed to get the same reading/exposure placement I get.
Thanks,
Do you have enough shadow detail for your preferences? If so, and there is too much contrast, it could be overdevelopment. Note this does not mean Kodak's recommended development times are wrong. Perhaps your subjects are high in contrast. Even if this is not the case, there are several variables involved in the amount of development that occurs given a fixed development time. How accurate and stable is the temperature? What is the agitation procedure like? How much agitation? It should not be difficult to get good results with TMax films.Quote:
Originally Posted by kbrede
This may be a decent place to plug my recent "article" listing a series of links to some Kodak and Ilford resources which can be quite useful to inexperienced and experienced workers alike. One of the links is to a short publication from Kodak on ISO vs EI. There are likely a lot of people who get the impression from Zone System books etc that they need to do a speed test because the speed on the box is wrong.Quote:
Originally Posted by Stephen Benskin
http://www.apug.org/forums/forum216/...resources.html
Michael just gave a nice summary of what can be happening. Part of the magic of using the directions is that it is normally well within the range of VC paper to adapt.
As to exposure the best book for me was by far, Dunn and Wakefield, Exposure Manual. It is out of print but typically available used. 3rd edition is what I have and is fine, printed as incident meters were becoming modern, 4th edition would be a bit more up to date in that sense but the concepts taught aren't different, either will be good.
Also Keaton that you find TX easier to use isn't a surprise to me. In the 100 speed range I find the same with FP4 when stacked up against TMax or Delta.
There is no shame in using films you find easy to work with.