GeorgianBay1939

GeorgianBay1939

Lives in Canada Ontario, Canada
Works as a Old doggie, learning new tricks
Has a website at https://brtthome.com/
Joined on Feb 7, 2013
About me:

I want to understand the in-depth fundamentals to inform my ability to make engaging images.
It is physically impossible for a camera to record what a human sees. There are two reasons for this. One is that no camera has the bandwidth, the adaptability, the responsiveness (transfer function) of the human vision system. The second is that the human vision system produces images in the visual cortex with is largely determined by the viewer’s previous experience. In other words visual stimuli travelling along the optical nerve stimulate a whole bunch of memories which combine to form what we see. What we see is uniquely personal.

Comments

Total: 4, showing: 1 – 4
On article Sense and Sensitivity (7 comments in total)

Very helpful article.
When you refresh it please correct the last sentence in the first paragraph: "As such it joins shutter speed and aperture as one of the three factors that define exposure." which is clearly incorrect.
A simplistic correction might be: "As such it joins shutter speed, aperture and scene luminance (Exposure) as another factor that determines the lightness (or brightness) of the final image."
Thanks for your good contribution to correct this often mis-understood and often mis-represented topic.

Link | Posted on Feb 22, 2017 at 12:09 UTC as 1st comment | 2 replies
In reply to:

Brian Kimball: Looks like you intentionally underexposed almost all of your shots, the exact opposite of what you want to do in snow.

A camera's meter will always underexpose shots with a lot of snow-- it doesn't know snow is supposed to be white, so it ends up exposing it to be 18% grey. You have to set a positive exposure compensation, not a negative one, to account for that.

Bummer!

RR22:
I am usually interested in seeing how much headroom* I have in the histogram or the zebra stripes when in the Liveview EVF, (or blinkies when chimping.)
informed by an in-camera JPEG.
So I want the relationship between clipping in the camera and clipping in the raw file as seen by RawDigger**.

*I define headroom as the different in stops between indicated clipping and clipping according to the raw file.
In my GH4, a mirrorless EVF, I find that headroom decreases with increased Exposure and with increased ISO. I don't have a precise calibration, that's why I shoot brackets. Seems dependent on each camera.

**RawDigger gives you a histogram of the raw values in R,G,G,B and you can easily see how far the top end is from the saturation level.

The above is seems irrelevant for OVFs users who set both Exposure and ISO using their camera's metering system.

I've no direct experience with FF vs MFT. My D750 and D800 buddies don't seem to outperform the MFT in snow.

Link | Posted on Dec 8, 2016 at 00:33 UTC
In reply to:

Brian Kimball: Looks like you intentionally underexposed almost all of your shots, the exact opposite of what you want to do in snow.

A camera's meter will always underexpose shots with a lot of snow-- it doesn't know snow is supposed to be white, so it ends up exposing it to be 18% grey. You have to set a positive exposure compensation, not a negative one, to account for that.

Bummer!

EE22: good examples of exposing for snow structure/texture. Why does Dan's imagery have almost no snow texture, albeit in flat light. I could understand if he were shooting jpegs, depending on a metered AE, but he shot many raw and converted in ACR giving him the opportunity to get some tonal resolution of the snow and sky. I suspect that bfk is right: The photog underexposed to protect highlights and didn't push highlights in post conversion.

I ignore metering when shooting snow. I shoot raw files, ETTR, using spot metering & AELock, very careful with highlights, informed by rawDigger-calibrated histogram and zebra striping(105%), EC if needed, bracket (-2/3,0,+2/3);; then pull back highlights, and push, shadows & clarity in post, usually LR6.

Some Examples/Experimentation: https://brtthome.com/2016/01/

Difficult to see the features of this camera being used to their limits. Perhaps the photog can tell us about AFC and AFtracking with moving skiers.

Link | Posted on Dec 7, 2016 at 23:08 UTC
On article Major Glossary rewrite complete (1 comment in total)

It appears to be time for DPR to again revise its "free online glossary".
Please see:
http://www.dpreview.com/forums/post/56285576
for some reasons why.

Link | Posted on Aug 24, 2015 at 13:26 UTC as 1st comment
Total: 4, showing: 1 – 4