Cheers for the detailed response HobbyUk really appreciate it. It has really cleared some of the information overload I ve been getting
It was a technique that I followed after reading a book on digital photography, about taking control in manual mode for consistency. If there are other easier techniques achieving the same result I am all ears
From your response I realize now that it does involve a lot of assumptions and if you get the placement wrong for the highlights it will affect the whole shot. But I will be checking LCD and histogram to assist at the same time.
So...what would be your method of tackling a typical scene that you are photographing.
1. Which mode would you be using
2. Would you just take a test shot initially and just check the LCD for Blinkies and histogram for tonal range and adjust for the shot accordingly?
Thanks in advance
1) Evaluative.
2) Yes, and push the histogram to the right.
Explanation (apologies if I'm teaching you to suck eggs
).
The basics of exposure setting are quite simple I think. You can make it as complicated as you like, and those that somehow manage to write whole books about it usually do.
First of all, I would say forget film. It is interesting from the point of academic understanding but film is different to digital, and slide film is different to negative film in terms of how you get the best from each. Digital has something in common with both, but is actually like neither.
What you are trying to do is take a typical scene which perhaps has a brightness ratio of maybe 1000:1. It may be more or less than that, but generally speaking it will be very much wider than the 128:1 that your average sensor is capable of recording. That's seven stops, and while you can argue the toss about that, the basic problem remains - trying to squeeze several quarts into a pint pot.
Fortunately, the
important tones in most scenes cover a much smaller range and the business of exposure is deciding what those tones are and making sure they fall within the dynamic range of the sensor.
The best way of doing that is to use evaluative/matrix metering, which takes dozens of readings from all over the frame. In doing so, it not only knows the average scene brightness, it knows the dynamic range, it knows where the dark and light ones are, and it knows what area of the picture they occupy. From this information, it can make a pretty good stab at the optimum setting, and furthermore it can 'evaluate' the data to shift things further if necessary. For example, if it sees a large bright area at the top of the frame, possibly coinciding with a distant focusing position if the lens reports that, it's a pretty safe guess that this is the sky in a landscape and it will make an appropriate adjustment. Evaluative is far more sophisticated than any of the other modes, and also much 'safer' - unlike spot for example, which is a risky option unless you know exactly what you're doing.
Evaluative will always get you close, if not optimum, with zero input from the user. Good for outputting straight from JPEGs. Just check the LCD with blinkies enabled to make sure you haven't blown anything important.
However, digital sensors record far more data at the highlight end and if you are prepared to do a little post processing of the Raw file, there is quite a lot more to be gained - at least one stop, maybe two or possibly even more depending on the subject. This is the principle of Expose To The Right (of the histogram) technique. (Good article here here
http://www.luminous-landscape.com/tutorials/expose-right.shtml )
What you do here is check the histogram/blinkies and increase the exposure, pushing the data to the right as far as you dare. The blinkies will start to flash and you then have to decide what highlight detail you want to retain, and what you are prepared to let blow to pure white.
When you have done this, not only have you maximised the tonal detail in the highlight end, there is a big difference in the shadows where an extra couple of stops of exposure really makes a big difference to the separation of darker tones and reduces shadow noise dramatically. Of course, you have now over exposed the in-camera JPEG which looks too bright, but when you pull it back down again in post processing of the Raw, you are left with cleaner highlights, richer and more luminous shadows, and minimal noise.
It looks great, but you have to make sure you don't blow anything important - that's the trick. Remember that the LCD/histogram/blinkies are all generated off the JPEG file and are therefore subject to the effects of all the camera pre-sets - picture styles, noise reduction etc. In particular, the contrast setting shifts the histogram/blinkes around quite a lot, so set that as close to zero as you can and you'll be pretty close to what you've got on the naked Raw.
