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Archive 2014 · Dual Light Exposures Discussion

  
 
Dalantech
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p.1 #1 · p.1 #1 · Dual Light Exposures Discussion


Here's a general discussion thread. I'll kick it off with my .02 and please jump in and add you're own.

Lately I've been shooting more between 1x and 2x, and getting back into field macro instead of "studio" work (the studio being my patio table). At the same time I still want to keep the background from being black, so that usually involves shooting at higher than normal ISOs or walking the shutter (decreasing the shutter speed to expose for the background). Increasing the ISO adds noise, but it also reduces the duration of the flash giving me more "stopping power". Decreasing the shutter speed only impacts the natural light exposure and it doesn't add noise. But if I'm not careful I'll get too close to the natural light exposure for the subject and if there is any movement it will get recorded. I was shooting this bee when the flash didn't recycle fast enough and I ended up with a dark frame. I kept it, and turned it and another exposure into a blog post. Here they are, and the first is obviously the shot without the flash.



Notice that I'm pretty close to the natural light exposure for that shot -you can see color in the critter's fur. Not good, since movement would be recorded (I was holding onto the sunflower with my left hand and bracing the camera on that same hand to keep motion to a minimum).

Now for the frame with the flash:



I don't like the specular highlights in that shot (the reason why I recently designed a new diffuser set). But you can see the subject being exposed with the flash, and the natural light is exposing the background.

Today I was out shooting and I put down some honey to slow the critter's down long enough for me to take a few shots. Baiting them also allows me to shade the subject so that I can use just the light from the flash to expose it, and I have the camera set to ISO 800 to pull some natural light out of the background.



A couple of things to note here: The sun was behind me and at a low angle. There was a mix of sunlight and shade in the background, and that accounts for the light and dark areas in that part for the frame. I shaded the subject with mu body and that allowed me to avoid picking up specular highlights from the sunlight -and possibly blowing those areas out with the flash. Also I took the time to take a test shot with the flash turned off to see what the scene looked like just with natural light. The flower was pretty much black, so I knew I could use the flash to freeze motion in that area of the frame since there was no significant natural light.

The very best conditions for this type of shooting are also the best for just using natural light: When there are high altitude thin clouds that act like a giant diffuser for the sun (no hard shadows). Then you can probably shoot without having to worry about casting a shadow over the subject since the specular highlights created by the sunlight will be weak. Plus if you need to shadow the subject you won't be casting a hard shadow over it -I've successfully placed my shadow over a critter without scaring it off under those conditions. The down side is that the amount of natural light that's bouncing back into the camera will be low, so you'll have to shoot at a high ISO and/or a low shutter speed.

Another thing to look for is the kind of light that I had today: Bright light at my back so that I'd get enough natural light to expose the background, but by shading the subject I could avoid natural light creating specular highlights on the subject. But shading the subject is pretty much a must.

Last for now: Shooting with a back lit subject with the sun directly in front of the camera (otherwise the background is going to be black). If the area behind the subject is dark then the background will be black.

Footnote: I'd really like for Birdie, and any other natural light shooter,s to jump in and add their observations to this thread



Nov 20, 2014 at 12:14 PM
e6filmuser
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p.1 #2 · p.1 #2 · Dual Light Exposures Discussion


It seems to me that, ideally, you want the subject in (preferably deepish) shade, with bright blues sky or brightly lit vegetation in the background. As insects will not be easily attracted into such shade, you might want to artificially shade the subject only during the shot. In practical terms, that sounds rather cumbersome.

Harold



Nov 20, 2014 at 01:06 PM
Dalantech
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p.1 #3 · p.1 #3 · Dual Light Exposures Discussion


e6filmuser wrote:
It seems to me that, ideally, you want the subject in (preferably deepish) shade, with bright blues sky or brightly lit vegetation in the background.


Exactly that.

e6filmuser wrote:
As insects will not be easily attracted into such shade, you might want to artificially shade the subject only during the shot. In practical terms, that sounds rather cumbersome.


It is, and more often than not you'll scare the subject off. But the alternative is to shoot in that bright sun and end up with specular highlights like this:



Lots of hot spots, some caused by the flash pushing the specular highlights created by the sun until they are blown out. Any area where the data in the histogram has been pushed past the far right (or left) hand side is an area where information (detail) has been lost. It's possible to adjust the white spot to pull those areas back in, but doing so will not recover the data in those areas. The computer will never be smart enough to recover information that's not recorded by the sensor, so the whole "fix it in post" mentality is a lie...



Nov 20, 2014 at 02:47 PM
Dalantech
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p.1 #4 · p.1 #4 · Dual Light Exposures Discussion


The other side of the natural light exposure problem -the background was nothing but heavy shade:



If you have anything to add please jump in.



Nov 22, 2014 at 10:50 AM





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