Once in a year opportunity : ) .... messed up. : (

Started Dec 1, 2013 | Discussions thread
OP GeorgianBay1939 Veteran Member • Posts: 4,044
Re: Once in a year opportunity : ) .... messed up. : (

Moti wrote:

GeorgianBay1939 wrote:

Moti wrote:

You did a remarkable job in analysing almost every point that lead you to fail a desired shot. It is nice to be able to find out what went wrong after the shoot but it is much nicer to think about these things beforehand and to be able to come home with a good photo.

Tha main reason for that is that you have a broad knoledge about almost every technical aspect related to cameras which is great, but you don't think as a photographer. Let me just give you two examples.

Biggest mistake, you didn't plan anything in advance. You didn't even define your subject. Is it the train? Is it only the lighting? So you go on a challenging mission without any planning, hoping that your technical knoledge will help you, well it didn't. As a former pilot you know that you go nowhere without a flight plan, same goes for a photography mission.

Another example, every photographer knows that on a challenging night mission, you always start with your best and fastest lens if you have it with you, and you had it. This is something you do automatically, without even thinking. Using your 35-100 at f2.8 would have given you a shutter speed of 1/24 instead of 1/6 which could have been the difference between fail and success.

That would have still blown the highlights of the coloured lights. That is why I would reduce the exposure by several more stops, EV*. (see calculation in the first post.)

The blowing/clipping of those coloured lights could've been minimized further by decreasing ISO to base 200. That would have left plenty of DR to lift the snow and rails out of their darkness.

In theory it is true but if you'd have known in advance that your aim is the lights and not the train itself, you'd exposed for the lights with a bit of shift to the right before clipping and you get what you want, with a faster shutter speed and less motion blur.

Image what that histogram looked like in the camera.?!  big spike at the left and a little trail to the right ... no spike on the right.  No information to ETTER.  The histogram was of no use to me.   Here is the Lightroom histogram of that image right after import of the RAW file.

Lightroom Histogram of converted RAW with no adjustments.

Why use the AE at all?  It metered several stops too dark.

Why not just use M(anual) mode, lens wide open and shoot at high shutter interval, at base ISO?

*In short, the image is horribly OVEREXPOSED, (using the proper definition of exposure

Now this is an interesting point. What is the proper definition of exposure or better to say, the definition of proper exposure. For me there are two ways to define proper exposure. The scientific way and the photographic way.

Can you give me a reference to the "photographic" way?  I must've missed it.  Very likely .... as I get somewhat frustrated with many texts and blogs that have their own pet definition of the term!  

I agree that using proper scientific exposure would have ended with a terrible overexposed image, because the desired outcome is not part of the formula.

I don't understand the above.

What happened in the above case is that the metering led to a terribly overexposed image by averaging out the luminance of the scene, averaging  it to give an output at 18% gray.  That is the way cameras work when set on one of the AE Modes, P, A, or S in the case of the GX7.  I don't understand what the definition of exposure has to do with it.

The photographic definition of proper exposure, at least for me, says - a proper exposure is the amount of exposure needed to make the image look exactly the way I want it to look.

I don't understand this either!   Where do you look at the image?  In the playback on the EVF?  On the LCD?

Not on the computer screen or print because that is too late to change exposure (EV) settings.  Yes, you can tweak brightness, lightness and all that good stuff in post processing but you cannot change exposure .... (except in Lightroom!   Because an illiterate labeled that "Exposure" slider, misleading thousands, maybe millions of beginning photographers, like me!)

Exposing according to this principle, could have given you exactly what you wanted.

Doesn't help me.

This is my (badly written) understanding of getting an optimal exposure using the train example:

If I had set my camera up properly I would've set my EV (f/, ss), to record the luminance of that scene, stopping motion blur, without blowing highlights.  In other words  I would've opened my lens wide, shortened the shutter interval, to get the greatest illuminance on the sensor without motion blur, (either camera shake or subject motion), without oversaturating those coloured lights.

Fortunately the shorter the shutter interval the sharper the image and the less chance of blowing highlights of the coloured lights.  But there is a limit to how high I want to go.   I also want to get a good exposure of the snow and context of the train.  So I stop at 1/250 sec and keep my ISO at base to give me maximum DR, allowing me to lift any shadows, if necessary at minimal (read) noise in post processing.

Usually I can count on the camera's exposure meter and histogram to help me.  In the above case the metering was heavily influenced by the dark and the histogram was of little value since it gave no high end (highlight) information.

I don't know if the above is the above is the "photographic way" or the "scientific way".

I have criticised the wiki definition of exposure as being weakly written.  Here is the link to that diatribe: http://www.dpreview.com/forums/post/52609244

Sloppy writing is sloppy writing ... whether in scientific texts or in photographic texts and should be corrected.   I hope that competent photographers will correct the (rare) fuzzy writing in Wiki.  Maybe that way a lot of the market-speak in the Brand blogs and Manuals (including mine) can be corrected.    Lots of examples, but lets leave that for another time.

I hope that this helps.




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