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[OM] Fessing up to GAS attack

Subject: [OM] Fessing up to GAS attack
From: Moose <olymoose@xxxxxxxxx>
Date: Sat, 16 Nov 2013 16:32:05 -0800
A combination of $ incentives combined with GAS and curiosity. A Panny GX7 
arrived via Big Brown Truck yesterday.

I had many questions, hopes and concerns. It will take a while to work through 
them all.

I can report a few things.

The electronic shutter works perfectly to avoid shutter shock. It eliminates 
the subtle, slightly odd, delay in shutter 
action/sound of an Oly set for 1/8 sec. delay. OTOH, it doesn't really speed 
overall acquisition of an image by much, as 
the 'shutter' takes about 1/10 sec. to record an image. Seems more 'normal', 
though.

The IS too seems to work well so far.

The dreaded rolling shutter effect does not appear to be an issue with static 
or slow moving subjects. The extreme 
examples seen on the web are just that. With ES, IS, 300 mm and a subject a 
couple of hundred yards away, there is no 
geometric distortion. This is roughly 1/4 of a frame. 
<http://www.moosemystic.net/Gallery/tech/GX7/GX7roll1.htm>

Yes, there are small differences, in focus and light/contrast, as well as 
size/shape. I looks to me almost like there is 
more increase in size than change in shape. I can't imagine finding one 
size/shape preferable to the other.

I haven't tried measuring it, but image write feels slightly slower than the 
E-M5, both with Sony Class 10, UHS-1 cards.

Sensor system differences are trickier. The Panny is definitely more usable at 
ISO 3200. It's not so much that is has 
less noise, but it's different noise, slightly finer grained, and only 
requiring lower setting in NeatImage to clean up. 
It may, but this is pretty subtle, retain more fine detail in non-test pattern 
subjects. More important than either of 
those qualities is that it doesn't exhibit the 'wormy' artifacts the Oly does.

Every camera I've used does this thing starting at some ISO level where there 
are odd, artificial lines hidden in the 
noise. Remove the noise, and they stand out. It could be easy to attribute them 
to the NR, but close observation shows 
that they are already there, just hard to see, before NR.

This effect doesn't show up with the GX7 until ISO 12800, two stops better than 
the E-M5. By then, the noise is quite a 
bit worse than either camera at 3200.  I think the upshot will be that the 
maximum practical, usable ISOs for the GX7 
for large prints or crops will be about two stops greater than the E-M5. 
Residual noise and slight loss of detail aren't 
as obvious as artifacts.

In the field, it may mostly mean better images at ISO 3200. That's as high as 
is possible with the ES, and the 
conditions where 3200 is needed are also those where shutter shock rears its 
head.

Some of you are likely asking yourself "What is he talking about, and who cares 
about such high ISOs?" A lot of my 
photography is done in the woods, and/or around dusk. A lot of it is of flora, 
where I want some DOF. The answer, which 
is a big reason I so love the digital revolution, is higher ISOs. I'm having 
such a good time getting good quality shots 
where I could get nothing with film.

I'm thinking how to post some samples. It's tricky getting everything 
comparable. Using the 135/4.5 on Auto Tube, I 
thought to eliminate most variables. The tube has a tripod foot, so I could set 
up and only change camera bodies. Hmmm 
... Critical focus somehow is slightly different, the images are slightly 
different sizes, and somehow not quite 
identically framed.

Then a lot of you folks don't have the detail vision I do, so I have to find 
really clear examples.

Fettle Testing Moose

-- 
What if the Hokey Pokey *IS* what it's all about?
-- 
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