Exposure technique info please

[ho_co]

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... as for checking focus from the DNG and the article in LFI, ... I think the article is in error. If you shoot JPEG as well as RAW with at least 2MP, you can much more accurately gauge focus than just the DNG. Just zoom in and try it

I'm afraid I don't follow. Where are these 2MP? You're right, though, I haven't experimented with it.

 

This has absolutely nothing to do with IR--I've never seen a focus issue to date that does--but it has everything to do with the size of the JPEG thumbnail in DNG alone

I may have confused you by trying to be succinct (heaven forfend!) in my first post (http://www.l-camera-forum.com/leica-forum/leica-m8-forum/28151-exposure-technique-info-please-2.html#post298175). Bültert's situation was: I'm using an IR-pass filter (B+W 092) with a lens not designed for IR focus. I need to know how far from visual focus the IR focus plane is. I try several different focus settings on the lens and compare the results on the preview screen to determine which one is best.

 

Bültert found that when the rangefinder was focused to infinity with the WATE, the best focus in the red+IR image was obtained with the lens set to about 3 m (op cit, p 47); since that amounted to a rotation of ca 8 mm, he applied that same rotational correction after focusing via rangefinder at other distances.

 

In some brief experiments with his IR techniques using the Tri-Elmar 23-35-50, I found as well that I got sharper results with that lens set to 10 ft for objects at medium distance to infinity.

 

But that is all beside the point and off-topic. I mentioned the article not to bring up the need to adjust focus with some lenses when using IR, but to mention my confusion at Bültert's mention of making focus verification on the red screen easier by avoiding JPG images.

 

As you said, I need to try it.

 

And we have two testers now getting different results--either (http://www.l-camera-forum.com/leica-forum/leica-m8-forum/28151-exposure-technique-info-please-3.html#post298832) the DNG previews are noisier but of about the same quality; or (http://www.l-camera-forum.com/leica-forum/leica-m8-forum/28151-exposure-technique-info-please-3.html#post298709) the DNG previews are much less sharp than the DNG + JPG Fine images. And those opinions both differ with Bültert.

 

Sigh.

 

--HC

[sean_reid]

Chris,

no worries..I sense I have a thing or two to learn about Histograms:o

 

regards

andy

 

Hi Andy,

 

One other thing to consider is that the LCD screen will give one an approximate (but not exact) sense of exposure (on most digital cameras). The fact that we can adjust the screen brightness, of course, is one reminder of this. That's not to say one can't work from the LCD image in checking exposure, just that it must require some practice to learn how the screen image was different from the actual file.

 

The histogram is more precise than the review image but that doesn't mean everyone should use it. To each his (or her) own.

 

Cheers,

 

Sean

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[Jamie Roberts]

I just tried this, and while you do get the same level of zooming, the quality of the preview images is quite different. In DNG only the previews are always soft (at least in my camera) while in DNG+jpeg fine mode, the previews are sharper and show more detail. I'm glad to know this because until now I have not been able to rely on the LCD to judge sharpness. Now maybe I can.

 

Bill

 

Exactly--the DNG only preview, zoomed past a certain point, is always a little soft. FWIW, the same is true for my other camera(s) too--this trick also works on the Canon full frame cameras (which is where I first noticed the difference!). The DMR, of course, doens't let you shoot DNG+ JPEG (at least, not that I can find with the 1,1 firmware!) so I can't say about that...

 

@ Howard, the 2MP I was mentioning was the cutoff in JPEG size, not resolution, to see the effect. I don't shoot full JPEGs on the M8 for proofing; smaller ones are fine.

 

LOL!! Thanks for the explanation, too, about *using IR* and focusing (as opposed to compensating for stray IR)!!

 

@ Ian--well, to each his own! I definitely see a difference, to the point of being able to tell if I nailed the shot or not, with DNG + JPG--zoomed in, of course.

[Frank Black]

Still hanging on this one,

 

Even if i seem to get 80% of my exposure right on the M8, i still struggle to understand the right way, if there is any,

 

I read that some people expose to highlights, compensating in post production for the shadows,but even tough when testing the highlights will blow when i try to compensate for the shadows,

 

Some expose for midtones,

 

About the histogram , some say it should be leaning on the right, but my best exposures are with the curves mainly on the center,

 

I like soft images, with a calm contrast, do not mind shadows and i hate blown highlights

I think exposure is the most important part of creating atmosphere in a photo,

 

Is there someone who can explain the most safe way of exposing correctly with the M8 ?

 

i Mean, been the M8 a kind of incident light meter (if i understand correctly) should i under expose ? over expose ? should i use the ev compensation?

 

Thanks for your answers

[Jeff S]

There have been many discussions about this since the 2007 thread you reopened. Here is but one that shows differing thoughts on "exposing to the right." There are many others regarding incident metering. And still more on post-processing techniques, which vary a bit based on the software you use. Your questions span all of these topics, and more.

 

Simply, incident metering is about as good as it gets to ensure no blown highlights. But, if you don't want to carry a separate meter, then using the M8 meter is not much different than using other reflective meters once you understand the metering pattern and exposure basics. Regarding the latter, these tutorials may be of some help.

 

For me, it's all about the print, so there are other variables and controls to ensure what you get in the camera translates to the print. But, this is a start.

 

Jeff

[Frank Black]

Thank you Jeff

 

i chose this one, because it was for me the one who made sense, even in the title topic,

 

Of course i could have open a new one,but there were so many that i chose to re-open

 

Sometimes a certain question is better posed, with a new input, even tough sometimes in this forum i note a certain critique to people when they do open a new topic or re-open a old one,

 

I appreciate your tips,

 

Forums are made for learning and sharing knowledge,

I read a lot on the web, i will read the links you shared, and will hope that more people will share their experience,