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 91 
 on: Today at 11:54:59 AM 
Started by ErikKaffehr - Last post by BartvanderWolf
Most people who use multiples specifically to reduce shot noise also take multiple dark frames to be able to subtract the read noise. It is only worthwhile if you are dealing with very low numbers of photons in the first place - astrophotography. Shot noise reduction is proportional to the square root of the number of multiples taken. Major PITA. You need it to image faint objects, but I can't imagine any non-astro / non-scientific situation where you would go to that degree of trouble in shooting and processing.

Hi,

A Raw converter like RawTherapee makes it easy. Just point it to a sub-directory with a number of darkframes and it will select and average them if multiples are present, and subtract their average from the Raw lights before demosaicing. It's implementation is not as sophisticated as in dedicated Astro photograhy applications, but then the average photographer has relatively many more photons available, although exposure times are much shorter.

Cheers,
Bart

 92 
 on: Today at 11:50:13 AM 
Started by dwswager - Last post by dwswager
Call me fickle but I tend to garner an appreciation of visual creatives by looking at what it is they do rather than reading what it is they say.

That is the best way to judge skill of the craft, but almost the worst way of judging technical competence.  You might be dazzled by a wonderful photograph, but the photograph may not in any way demonstrate the technical point being discussed.

I judge myself as mediocre as a photographer because I don't have a great eye, but even I produce a great photograph from time to time.  Neither has anything to do with technical knowledge.  I can show you a poor example or a great example and you would draw 2 different conclusions.

Like I said, photographic evidence is great and might be the only way to get help on a particular issue.  Things like "Why did I get this..."  a photo attached.

 93 
 on: Today at 11:49:49 AM 
Started by DeanChriss - Last post by NancyP
All Canon DSLRs come with the standard neck strap, on which there is a small rubber plug similar to the Nikon version in the previous post. Failing that - careful application of your hat, approximation of your thumb to eyepiece, or gaff tape! Not usually a problem for me because I use live view on tripod, and my eye is on the eyepiece if hand holding.

 94 
 on: Today at 11:49:31 AM 
Started by dwswager - Last post by armand
Let's add a little perspective to this: Should a football coach (be that American also) or a boxing coach be able to play the sport well to prove its worth? Or are the art critics renowned for their work? Just saying.

 95 
 on: Today at 11:46:42 AM 
Started by dwswager - Last post by NancyP
Agreed, on the internet not only is there a temptation to be rude, but one has to be careful not to write something that could be interpreted as rude by someone who doesn't see your facial expression / tone of voice and doesn't know your writing style.

On the other hand, sometimes people really want to see exactly what your problem shot looks like. Valid - am I the reader missing something? OK, so I am a huge geek. I want to learn technique and the mechanics/ science behind the image, as well as how to create a meaningful image. I tend to look for geekery in the equipment fora and aesthetics and philosophy in the image fora. But sometimes, as in the current dynamic resolution thread, actual images are really helpful.

 96 
 on: Today at 11:45:14 AM 
Started by ErikKaffehr - Last post by BartvanderWolf
I wish that were the case! If glare was actually applied evenly, essentially adding a fixed amount of light to every point in the image (which could equal four or five stops in the shadows, but a fraction of a stop in the highlights) it would essentially work as a giant fill flash, reducing the dynamic range of the scene and making it easier to capture. Unfortunately it is not, and doesn't really reduce the DR across the whole frame - merely where the lens flare is.

Veiling glare contributes/adds mostly to the shadows where signal levels are low. Since the glare is a product of intra-lens and inter-lens element/group reflections (aggravated by dust and atmospheric deposits), it is not confined to the regions where light is (besides the lens receives all scene light everywhere on the lens before it is finally focused on the sensor).

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Fortunately, it's usually easy to completely shield it with a well-placed hand forward of the lens but outside the field of view.

Some of it, yes, but it would take unwieldly deep petal-shaped lens hoods to really do a good job. Hence the on average mediocre shielding peple use if it's even given proper attention to begin with. I use a different lens hood on my TS-E 24mm II when not using it shifted, or only a little. The EW-88C to which I added flocking material, does a better job, even though it was designed for a different lens. I use a separate (Lee bellows) if I want something deeper, and have a petal shaped design ready for 3D printing if that makes enough of an additional difference.

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Doesn't work when things are moving. In landscape photography, wind is the usual culprit.

On the contrary, it works fine in most cases. It's often not the horizon line or other moving features that are contrasted with the brightest parts of the image. Most of the info is in a single shadow exposure shot, and only parts are in the ETTR highlight shot.

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I often do that. Functionally, it's the same as halving the ISO - you're collecting twice as many photons by exposing for twice as long, so each photon counts for half as much. It certainly minimises photon shot noise. I'm not sure that it actually increases DR, though, since the read noise is also counted twice.

Yes, photon shot noise gets reduced, but averaging also averaged read noise. It does it so well, that pattern noise will be better visible. That's where improved sensors (and/or black frame subtraction) will shine, that is by absence of pattern noise. The patterns become more noticeable because we humans are good at pattern recognition, even where there are none we see details (like shapes in clouds, or faces in moon rocks).

Cheers,
Bart

 97 
 on: Today at 11:42:23 AM 
Started by ErikKaffehr - Last post by shadowblade
Most people who use multiples specifically to reduce shot noise also take multiple dark frames to be able to subtract the read noise. It is only worthwhile if you are dealing with very low numbers of photons in the first place - astrophotography. Shot noise reduction is proportional to the square root of the number of multiples taken. Major PITA. You need it to image faint objects, but I can't imagine any non-astro / non-scientific situation where you would go to that degree of trouble in shooting and processing.

Dark frames only work for removing fixed read noise (including fixed pattern noise), not random read noise.

 98 
 on: Today at 11:42:12 AM 
Started by DeanChriss - Last post by dwswager
Perhaps I've lived a sheltered life but I've never had a DSLR, or 35mm film camera for that matter, that did not have a built-in eyepiece shutter. That may soon change and I'd like to know the best way to deal with it. For photographing wildlife or action there's no need for an eyepiece shutter since your face and eye blocks light from the viewfinder. For landscapes I use it 100% of the time if I'm not using live view, and I don't use live view very often. Unless environmental conditions are nice and the scene will remain as it is for a while, which is rare, I want to work reasonably fast without lots of fussing around. I can't imagine being in a hurry, in the spray of a waterfall, blowing sand, or countless other "not nice" conditions while having to remove the eyepiece surround and replace it with a rubber cover. I also canít imagine not losing one of these pieces eventually, or trying to get gaffer's tape to stick to a wet camera, or using live view when there are beads of water all over the LCD or dust blowing into your eyes.

I'd just like to find out how people deal with the ridiculous lack of a built-in eyepiece shutter on many cameras. Has anyone found a clever solution, like something that slides into the hot shoe and flips up out of the way? I donít care what it looks like but it has to work.  I know this seems like an insignificant issue, but exposures that are off due to stray light entering the viewfinder are as significant as it gets for a photograph.

Thanks.


Nikon DSLRs without eyepiece shutters come with a little piece of plastic that looks like a hot shoe cover piece.  The cameras with a rectagular viewfinder window.  I would think other brands provide something similar.  If the exposure isn't excessively long, the I wouldn't worry too much unless the intensity and angle of the sun is right into the viewfinder window.  And you can just shield it with your hand or a dense cloth.  I have not mastered Live View for focusing so I switch back and forth.  In bright sun I use a cloth over my head to shield the screen so I would use that on any camera without a shutter.



Apparently, there are Round Viewfinder Nikons without a shutter because I found the DK-8


 99 
 on: Today at 11:41:52 AM 
Started by Theodoros - Last post by rsmphoto
The MF forum on Lula used to be a gathering place for knowledgeable pros and serious amateurs to discuss real issues are MF photography. Now it's mostly the same people, having the same tedious conversation with themselves, over and over and over.  It drives out the high-value people and diminishes the value to the general readership.

The 'S3' aka 007 will come out when it comes out.  In the meantime, like my girl Taylor says, the pros are gonna shoot shoot shoot shoot shoot, and the wankers gonna wank wank wank wank wank and I'm just gonna shake shake shake shake shake.... 

Indeed. Hypothesis, postulation and statements of authority seem to appear frequently, but all too often with no real information - more, ephemera.  But like a reality show, it can make for a bit of entertainment when the inevitable offense is taken, or offered. Wink

Shooting'...... and shakin' here.

 100 
 on: Today at 11:39:42 AM 
Started by ErikKaffehr - Last post by NancyP
Most people who use multiples specifically to reduce shot noise also take multiple dark frames to be able to subtract the read noise. It is only worthwhile if you are dealing with very low numbers of photons in the first place - astrophotography. Shot noise reduction is proportional to the square root of the number of multiples taken. Major PITA. You need it to image faint objects, but I can't imagine any non-astro / non-scientific situation where you would go to that degree of trouble in shooting and processing.

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