Dragging the shutter, thoughts.

I've been thinking a lot about flash photography lately, it represents something of a dark art for me. I understand the theory behind it, it isn't too complicated. I do struggle with quick situations where I have to work out settings FAST to take a good photo. There are a lot of things to consider with regard to accurate flash exposure, for foreground and background. Not to mention ALL the standard photography rules, about focus technique, and composition.

So, with dragging the shutter, imagine the following situation. The background meters at 1/20 at, say, f/4. The foreground (perhaps a person) is also registering 1/20 at f/4, so we have quite an even situation, 1/20 @ f/4 will perfectly expose everything.

In situations like this (foreground and background equal light), is dragging the shutter possible? I see the following possibilites.

1 - You expose at 1/20 @ f/4 and fill flash....the background exposes perfectly, the flash will kick out hardly ANY power at all (because the subject is already going to be exposed nicely at 1/20, f/4). As such, the foreground subject is exposed well, but a bit blurry because of camera shake (due to 1/20).

2 - You decide to either increase shutter speed or close down the aperture (e.g. 1/60 at f/4) - so effectively you reduce ambient light coming to the lens. This means the flash will have more impact and weight, but the end result is an underexposed background, and perfectly exposed and sharp foreground.

It's a basic view of what might happen, but it's just something I was thinking about today. Obviously the best option is (2), because you do get a useable photo. So is it a fair thing so say that if your foreground subject and background are metering identically, then you can't really get much success at 'dragging the shutter'? Dragging the shutter is only a possibility when the background ambient lighting is brighter than your foreground ambient lighting?

Or, you could read all this and decide to ignore the inane ramblings of somebody bored at work.

The ultimate aim is for me to know exactly what my camera is going to do, rather than be reactive to what it actually does when I try it.

Read this thread, lots of info.
https://photography-on-the.net …p?t=138130&high​light=lime

>>2 - You decide to either increase shutter speed or close down the aperture (e.g. 1/60 at f/4) - so effectively you reduce ambient light coming to the lens. This means the flash will have more impact and weight, but the end result is an underexposed background, and perfectly exposed and sharp foreground.<<

Alternative 3: You do not need to fully see the background brightly in the photo, but you can capture it in a subdued manner, with existing lighting (e.g. recessed lighting) providing better lit areas within the background area and providing ambience. So you set the lens to f/5.6 and drag the shutter at 1/20, but the flash fires and provides the lighting for a correctly lit main subject.


>> So is it a fair thing so say that if your foreground subject and background are metering identically, then you can't really get much success at 'dragging the shutter'? <<
Nope, wrong assessment. See my Alternative 3.

>>Dragging the shutter is only a possibility when the background ambient lighting is brighter than your foreground ambient lighting?<<
Nope not at all. Dragging the shutter applies any time the background is dimly lit, regardless of the relative brightness of the subject, where the flash 'takes care of' the subject, and the background gets captured by the use of a slow shutter speed in combination with appropriage f/stop using ambient light.

Apologies...I realized, after the post, that my Alternative 3 was described adequately in the general Alternative 2 description of the OP.

Hi Wilt,

Your alternative 3 is the same as my alternative 2 - you are reducing the ambient light entering the lens. It's just that I used shutter as an example, you use aperture - the end result is the same.

Also my question "Dragging the shutter is only a possibility when the background ambient lighting is brighter than your foreground ambient lighting?" should actually read,

"Dragging the shutter with acceptable results is only a possibility when the background ambient lighting is brighter than your foreground ambient lighting?"

For this (deeply) theoretical situtation I am assuming that we want the background perfectly exposed, not underexposed/subdued at all.

Hehe too quick to reply!

I've read the thread above, it actually started to get me thinking, so I took some test shots myself.

As I said in my first post, the ultimate result is having perfect knowledge of what the camera is going to result in - that is the goal.

I figure critical assessment is needed immediately prior to taking the photo. As a photographer you must ascertain the relative lighting of foreground to background to know fully what is going to happen.

If the foreground subject is brighter than the background (maybe only slightly), then you are going to have a very hard time getting a properly exposed background in your picture, without sacrificing the foreground. It's this sort of knowledge that I am hoping to make second nature so that less time is spent wasting effort in certain photographic situations. It sounds obvious, and it is, but without explicitly looking out and accounting for a situation like this, I would waste a shot (not a problem) and potentially waste an opportunity (big big problem!).

>>"Dragging the shutter with acceptable results is only a possibility when the background ambient lighting is brighter than your foreground ambient lighting?"
For this (deeply) theoretical situtation I am assuming that we want the background perfectly exposed, not underexposed/subdued at all.<<

Yup, if the BG level was same as FG level, if you dragged the shutter, there is really no point to using the flash (since the FG would be as properly exposed as the BG) other than to open up shadows cast on the fast (in which case it would be called 'fill flash' not 'dragging the shutter')

>>other than to open up shadows cast on the fast <<

Typing too fast "other than to open up shadows cast on the FACE"