Massive A77 Flash Test (14-image series)

Started May 18, 2012 | Discussions thread
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jl_smith
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Massive A77 Flash Test (14-image series)
May 18, 2012

Here we go folks, as promised. I've tried to determine just what my camera is doing when using flash.

First, a photo of my setup. Ignore the mess, this room is under construction.

Camera parameters - Factory reset, then changed to JPEG Superfine Small, SSS and DRO were disabled. Initial lens was the 35mm 1.8 SAM that later changed to 16-50 SSM. Apertures were shot wide open until greater than 1/250s SS was hit, in which case aperture was closed down below the limit. Note factory default using evaluative metering.

How To Read the Test

Each test builds from the previous test , meaning for instance if a test says "Flash Comp -3.0" then the very next test only says "43AM mounted", this means it has retained the previous setting of "-3.0".

Also, some astute readers may see my test #s on the images skip and/or become "unsynced" from the image names - don't worry about this, as I was just making my file names "sync" to the title pages I had shot to help queue up the tests in Lightroom.

To read the image series , you start at the top-left with ISO 100. Move top-center for ISO 200, top-right for ISO 400, bottom-left for ISO 800, bottom-center for ISO 1600 and finally bottom-right for ISO 3200...just like reading printed English.

Methodology

A77 placed on tripod and set to parameters listed above. Room lit by two 55W fluorescent lights (I think around 1600 lumens output but I'm not sure). The left-hand light was hitting the "subject", in this case a basket of Barbie dolls, a bit indirectly. This creates a very slight "shadow" on the right of the basket, perfect for a fill light situation.
This subject was chosen as a medium-toned object a bit larger than a human head.

Camera plane started at 4 feet away from subject, then is moved to 5 feet, 10 inches later (shows this in the test). Also, the ceiling is white and 5 feet, 6 inches above where the flash head rests. The left and right walls are around 5 feet from the camera. Behind the subject, low ambient light from a window blind was blocked using black velvet cloth.

The below photo shows the relation of the subject to the camera, to show it covers a majority of the frame and therefore should use most of the metering data.

Also, note this is the view once spot metering was chosen:

First, I took a photo of a piece of paper showing the relevant parameters. Afterwards, starting at ISO 100 (and double-checking my parameters), I took photos in whole-ISO stops up to ISO 3200. Please read above to determine which photos are which ISO.

Afterwards, I imported all JPEGs into LR 4.1. I selected all 6 in the series, exported to Photoshop CS 5.1 (editing in Layers). I then resized the canvass to 9024 x 4000, moved the images to be in the proper spots, resized back to 1600 px wide, typed the test parameters then exported to JPEG.

I double-checked the Lightroom Catalog and Photoshop files to ensure the files were "synced" and that I was naming the correct series with the correct test number. Ignore the fact that on the photos, I seem skip test 5 label - this is done intentionally by me.

On the next reply, I start the test results.

Exif probably won't exist since these are compilations of 6 images - if anyone wants an original JPEG posted, please ask me to post "test number, ISO number" and I can, as I kept the original shots.

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