Grain and noise

StephenM

StephenM

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This is a genuine attempt to understand something that puzzles me.

In the TalkPhotography section, there's currently an active thread "Excessive noise creeping in". That's what started me thinking along these lines:

1. "Noise" is said to be the digital analogue (see what I did there?) of "grain" in conventional photography.
2. As far as I can see, "noise" in a digital image is deprecated.
3. Many conventional photographers like grain.

This is a puzzle to me as it stands, so I suppose that the solution is one of

1. "Noise" isn't the same as grain; it's more intrusive (point 1 above is wrong)
2. Some people like the coloured speckles to add interest to the shadows (point 2 above is wrong)
3. Conventional photographers mainly (nowadays) come from 35mm backgrounds and grain is almost inevitable, so they just have to make the best of it.

Seriously, what am I missing? Why is noise bad and grain good?

I know that I'm one of the odd people who don't like grain, and that's one reason I don't use 35mm. But setting my prejudices aside, what's the difference?
 
Welllllll, I think the causes are different -- if I understand the digital bit (hah! See what I did there?) correctly, grain is related to the physical structure of the film, while noise originates with not having enough light (and in a way does relate to grain).

As someone who does come from a film background, I remember that we weren't always in love with grain. Back in the early 90s, when I got started in earnest, I shot films like T-Max, Ektar 100 and Velvia specifically to *avoid* grain. (Well, okay, I shot the Velvia because it was free. Did I realize how lucky I was back then? No.) Despite living in Rochester, New York, I secretly shot Fujifilm 1600 because it had less grain than Kodak Ektar 1000. I was a grain-hating grain avoider. I also shot Ektar (versus, say, Gold) because of the bright, bold colors it gave me.

Nowadays, I shoot primarily B&W traditional-grain films, and my low-light solution is HP5+ @ 1600, pebbles and all.

Why the change in attitude? When did I go from grain-phobic to grain-friendly?

I guess it was the switch to digital. All the things I wanted from film -- bright punchy colors, sharp images, minimal grain -- are easy in digital. And when I shoot B&W in digital, something about it feels a bit artificial... the shots are just a little too smooth, a little too perfect.

I don't shoot much color film (for a variety of reasons, largely related to the type of photography I do, I prefer to shoot color w/ digital), but when I do, my favorite film is ColorPlus 200. It's got that nice washed-out, faded-memory look that I spent so many years trying to avoid with Ektar.

So maybe it's wanting what we cannot have that causes so many to embrace grain?

Maybe when digital is replaced by something else (cameraless neural-net photography) that eliminates noise, we'll miss it. Maybe the kids of today will "discover" old 23.4 megapixel cameras, then crank them up to ISO 51,200 and brag about the authentic digital noise, deriding the digital-noise simulators in modern non-camera cameras as poser fakery?

That's my guess!

Aaron
 
It just seemed odd to me that analogous artefacts should be regarded so differently in the two camps. It makes more sense after reading Aaron's post, that film users simply want to make their photographs look different simply as a point of difference; and that without being up against grain free digital then they would prefer grain free. That I can understand.

I like the thought of you sitting twitching, and idly wonder if the verb is to be construed as transitive or intransitive and if the former what the neighbours make of the semaphore signalling curtains...
 
I don't think noise is the same as grain but I also think that noise has been turned into a fetish by digital camera manufacturers who are using it as a marketing ploy to say why one should upgrade to their newer model, i.e. lower noise.

I might be wrong here but I think grain is essentially uniform across the frame, it might be more visible in some parts of an image but it is everywhere. Noise, whilst presumably uniform in the RAW file, is often exaggerated by trying to lift poorly exposed shadows and hence is not uniform across the image and as such is perhaps seen as occurring because of of poor exposure and processing rather than as something that is inevitable. Noise also occurs as random colours which can seem quite bright/vivid if "pixel peeping".
 
Add to all that "sharpness". Feels like everybody is obsessed with pin sharp images these days, it's like the human brain is loosing the ability to fill in the blanks. The same applies to an old film shot with grain and a digital image with noise.
 
I take the point that for advertising purposes, camera makers want to portray noise as bad, if it means that they can sell an newer model. On the other side of the great divide, film camera makers wouldn't be able to do the same thing, as the only way to reduce grain is to use a slower film or upgrade to a different camera maker (usually), and I don't see Nikon saying "you'll get less grain if you buy a Hasselblad".

My understanding of noise was that it was a signal to noise artefact, and hence would be proportionally more present in darker areas where signal boosting (and hence false positives, if you like) would be greater. Grain is present right across the frame, but certain things present within the image do affect it, insofar as extra exposure results in larger grain, and so skies are more likely to exhibit grain than a mid grey tarmac.
 
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Tests have shown that actually people perceive a print with grain as sharper than one without. One of Barry Thornton's books discusses this point. Rather like the very old images used when mtf first became popular in amateur magazines back in the 1960s and the Zeiss (I think) image of a stained glass window was shown to demonstrate that in terms of perception, a high contrast low resolution image looked sharper than a high resolution, lower contrast one.
 
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StephenM said:
hence would be proportionally more present in darker areas where signal boosting (and hence false positives, if you like) would be greater.
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As I understand it noise initially comes from amplifying the signal from the photosite on the sensor and is proportional to "ISO", more amplification (higher ISO) gives more noise. I'm not aware of any cameras that can have different ISO for darks and lights so I don't think there is more boosting in the darks but for a fixed amount of noise the bright areas have more signal so a lower signal to noise ratio.

StephenM said:
Tests have shown that actually people perceive a print with grain as sharper than one without.
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That's interesting, is there an objective way of measuring sharpness? Could it be that the techniques used to reduce grain actually also reduce sharpness?
 
On the first point, I think you are correct. I had more in mind the signal boosting inherent in trying to boost low light.

On the second, it is partly a matter of perception, but in some cases there would be an objective loss of resolution. If you want to carefully photograph test charts and count lines per millimeter with a microscope (or whatever), you should find that if you use a fine grain developer which usually (always?) works by a solvent effect (i.e. dissolve away some of the silver grains) this does reduce the resolution.
 
The idea I've seen to explain the subjective sharpness phenomenon is that faced with two prints, fine detail always makes the print possessing it seem sharper. If the two prints lack very fine detail, visible grain steps in to fill the gap, gives the eye something to focus on, and creates an effect of sharpness - even if, without grain, that image might actually be slightly lower in resolution.
 
Just to throw another spanner into the works: a lot of "graininess" in film images was actually reticulation.

Sometimes reticulated images are obviously so but never underestimate the ability of a photographer in a hurry to produce effects that a good darkroom operator would struggle to repeat!
 
Kodak HIE is/was a notably grainy film, and had a look that was totally acceptable to me and others. OTOH, the noise on my IR (830nm) converted Panasonic G5 I find to be annoying if shot at the same iso400 as the HIE, because it looks different. There are those who prefer the look of traditional mono films to T-grain films, even when grain might be about equal in quantity, though not in appearance. I've also seen opposing views on whether Fomapan 100 is "better" than their 200 hybrid-grain film, and some of the views are quite strongly held on this, which was interesting as I was intending to buy some sheet film from them.

We might then look at format, where I don't like HP5+ in 35mm yet am happy with it in 120 and 5x4 in the same developer, yet there are others who produce great shots with it in 35mm.
I haven't shot enough Pan F to compare it, but Acros is/was very popular for its lack of grain and its great reciprocity characteristic, which is why some of us stashed it in the freezer when the original version was discontinued.

And then of course there is subject matter, where grain may either help or hinder a photo, particularly social/wedding type photography as opposed to street or news type shots, which is why Portra and previous films were introduced. We're never likely to do handheld bird photography with iso100 films, so faster films are pretty much essential and a lack of grain would be desirable for enlarging a subject that may not fill the frame. This may be one area where digital scores higher than film, but that's only for those doing that type of photgraphy.

My photography is fairly static landscape work, with some moving subject shots but no really fast moving subjects. While I was always a Fuji transparency shooter rather than Kodak, I could happily have existed with Kodachrome for colour and Acros for b&w, so not really a grain lover I guess. :thinking:
 
For me, it's just a subjective thing. When I upgraded from a Canon 350D to a 50D I whacked it up to 800 ISO and the results were just awful. The "noise" was plain ugly to me.

When I develop HP5 in Rodinal, I get similar results. The grain has an ugly mushiness to it.

HP5 pushed to 3200 and developed in DDX. The grain looks beautiful.

I can't logically explain why this is. Sorry :)
 
Harlequin565 said:
HP5 pushed to 3200 and developed in DDX. The grain looks beautiful.

I can't logically explain why this is. Sorry :)
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Thanks for confirming my suspicion that liking grain is irrational :p
:exit:
 
Woodsy said:
I'm sat here twitching a bit :D

As for why people like certain things and not others, I suppose it's just a personal thing - like why some people like marmite and some don't.
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Did someone say marmite? *moves toaster, fresh white bread and butter into position*
 
When I were a lad, we didn't have these new fangled things like toasters. We had the real thing - toasting forks and a proper coal fire to toast on. The fire added what chefs call "an extra layer of flavour" to the toast. We called it soot...
 
Stephen, I think grain and noise are similar. Digital noise is based on random electron activity and grain is due to the random distribution of silver halide molecules in film. I do not like it in either and it is a feature of small formats an high ISO in both cases. While many decades ago people were more tolerant of grain which was probably as well give that the early digital cameras were rather noisy. I have been using FF Canon 5D4 for a few years now and noise has rarely been an issue. However, recently to reduce weight, I moved to a half frame Sony ML camera which has many advantages but definitely produces more noise. Fortunately this coincides with the availability of much improved noise reduction software. As with many things this has happened before . Even in painting George Seurat used his pointillism style which is like noise.

Dave
 
Thanks David, and especially for the reference to Seurat.
 
sirch said:
As I understand it noise initially comes from amplifying the signal from the photosite on the sensor and is proportional to "ISO", more amplification (higher ISO) gives more noise. I'
Click to expand...
I've been witness to/involved in about a billion arguments about the source of noise on Those Other Forums, and what I'm about to say is me parroting what I have read -- I'm far from an expert here. The concept as I understand it is that noise is basically from a lack of light, and that higher ISO doesn't so much create noise as reveal it, since it's used on photos where light is lower and therefore the exposure is smaller. Apparently there are situations where raising ISO can decrease noise -- but that's getting into the realm of expose-to-the-right and .RAW file processing, things I haven't had the time to learn. When I'm not shooting film, I'm usually a straight-out-of-the-camera .JPG kind of guy.

Aaron
 
Grain, noise, sharpness…… perfection or imperfections.
As already mentioned, it’s subjective in the same way that the actual image content, composure and exposure is of personal preference.

IMO both noise and grain can be productive or non productive ( good / bad) …… it simply depends on the desired result.

Even then , does the desired result have to be perfect?
If so then what is perfect?
I have no perfect results .
Few, if any are technically perfect ( based on so called rules of composition, exposure, grains etc),

Sometimes the imperfections put life into an image that otherwise wouldn’t be there.
 
On film, I liked either as smooth as possible (so as little grain as poss) OR exaggerated grain (but only in B&W shots). On digital, I try to avoid noise as far as possible and if it gets too much (for my tastes), I try a B&W conversion or noise reduction software, although excessive NR can soften an image too far.
 
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