Fast Stacking and Continuous vs Flash Lighting

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newtonsapple
Posts: 11
Joined: Mon Jul 20, 2020 8:39 pm

Re: Fast Stacking and Continuous vs Flash Lighting

Post by newtonsapple »

So I got an 80W COB light that was on sale (Prime Day) to just understand what is involved in lighting these objects.

The light I got was a GVM-P80S. https://www.amazon.com/gp/product/B088K ... UTF8&psc=1 I got what is apparently the newer version that has an LCD display on the back showing the power setting. Output (of the 1st version at least) is supposed to be just a little more than an SL-60w.

From playing around, the immediate realization is that these large COB's generally throw a spot size that is much larger than is useful at a reasonable working distance. It can deliver the require intensity, but there is a lot of wasted light. For most macro diffusers we need to cast light on a 1-4" area depending on the diffuser setup. This COB, without the bowens hood, throws a 4-5" spot at just 1-2" (hand holding and estimating). There is a fair bit heat at that distance. It would actually be workable for my plastic and metal subjects, but still warm. The light is pretty in the way at that point and you are lightly turning the power way back while still getting good shutter times. Backing the light up further just increases the spot size, much of which is not useful as it is not landing on your final diffuser. You can snoot it down, but I suspect the actual delivered light intensity is not very efficient through a snoot.

So the next objective is smaller, more focused COB's and reflectors that can be positioned close and provide the required spot size. This way there isn't a lot of wasted power.

chris_ma
Posts: 570
Joined: Fri Mar 22, 2019 2:23 pm
Location: Germany

Re: Fast Stacking and Continuous vs Flash Lighting

Post by chris_ma »

you could try to put a 2-4" diameter aluminium tube in front of the COB to guide and concentrate the light.
still a bit of wasted light, but probably quite a bit brighter in the center and already diffused a bit
chris

newtonsapple
Posts: 11
Joined: Mon Jul 20, 2020 8:39 pm

Re: Fast Stacking and Continuous vs Flash Lighting

Post by newtonsapple »

chris_ma wrote:
Thu Jun 24, 2021 3:12 am
you could try to put a 2-4" diameter aluminium tube in front of the COB to guide and concentrate the light.
still a bit of wasted light, but probably quite a bit brighter in the center and already diffused a bit
This would help some. A black snoot will not change the intensity of the delivered light, just cut it off the excess. I don't know how much "boost" a reflective ID would add. My guess is it still wouldn't be very efficient vs a 10-20w COB and a small reflector that can be positioned 1-2" from the main diffuser. These are big lights to fixture and maneuver and you likely aren't gaining a lot for the size/power.

lothman
Posts: 957
Joined: Sat Feb 14, 2009 7:00 am
Location: Stuttgart/Germany

Re: Fast Stacking and Continuous vs Flash Lighting

Post by lothman »

I use Viltrox RB08 LED panels, high cri, dimmable, color temperature adjustable, USB rechargabel, magnetic clip on diffuser around 25$ on aliexpress.

TheDocAUS
Posts: 110
Joined: Thu Jul 19, 2018 10:44 pm
Location: Sydney

Re: Fast Stacking and Continuous vs Flash Lighting

Post by TheDocAUS »

The Post Focus feature on Panasonic cameras may help here. I use the feature (G9 camera) in the field with a small Sokani LED as my light source. The camera creates a 6K video, the frames are extracted and then stacked. The in-field workflow in all about speed, as is my desktop workflow. I sacrifice some quality, but not much, for the speed.

Helicon Focus extracts the frames from the video. But I can use Helicon or Zerene to do the stacking (I use both). For Zerene I import the images from the Helicon cache and then stack. Zerene cannot extract frames from the 6K video, Helicon can. You must keep Helicon open while staking in Zerene, because closing Helicon clears the cache.

I use a 30mm macro or 60mm Olympus macro lens giving me 2X or 2.5X. You can also use a Raynox DCR150 or DCR250 on the lens to get up around 4X to 5X. The Raynox limits the working DOF.

Post Focus videos commonly take 2-5 seconds after the shutter is pressed. At the desktop extracting the video using Helicon takes under 60 seconds, another 30 seconds for post processing and 30 more for sharpening. I use a fast graphics card that utilizes OpenCL (which helps in Helicon and with sharpening). It will take longer if I use Zerene to stack.

Sample images reduced to 1920 pixels on long side are here: www.users.on.net/~mhains/lrbg.zip

The images (not the colour palettes) are roughly half the size of postage stamp or around 18mm x 135.5mm.

My full workflow is spelt out here: http://www.photomacrography.net/forum/v ... 25&t=37904

If you have detail in an area where there are no AF points, the camera may not take images and you can miss details. This tends to be around the edges, but it can happen well inside the frame. It is normally fixed with recomposing the image.
Last edited by TheDocAUS on Fri Jun 25, 2021 1:55 pm, edited 1 time in total.

newtonsapple
Posts: 11
Joined: Mon Jul 20, 2020 8:39 pm

Re: Fast Stacking and Continuous vs Flash Lighting

Post by newtonsapple »

TheDocAUS thanks for your post. I just read through your whole Post Focus thread and it is pretty interesting and an approach I will consider.

I got Helicon remote working with the Nikon Z50. I had it in video mode...doh.

Now I need to work out the backlash settings on the Stackshot as setting the front and back focus points and then cycling through them, they don't repeat. I need to play around tonight as it should still work fine driving in one direction, which means needing to drive past the starting point on return.

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