Recently I posted some photos I had taken at night. In that post I started waxing philosophical about how digital cameras interpret the scene. Wah has promised that if I post more of the photos he will argue with me about that claim. I’m excited about this not because I love to argue but because Wah knows way more than me about photography. So…Here are a few more pictures from what might be called my “Night Shots Series” if I were inclined to think that I worked in series-es.
This is a tree behind the Bilmore Hotel in Miami. I really like this tree; you can see that it has grown over the wall. I also like the different kinds of light in this picture. There are those heinous sodium-vapor lights that illuminate part of the background, which gives it an orange tinge. But, in the foreground the light as much whiter, which is causes the green to be so…well, green. The sky in Miami is just so amazingly bright all the time.
Compare the sky in Miami to the sky in Tampa. Though, to be honest, its not a fair comparison. The photo from Miami had a 15 second exposure while this Tampa photo only has a 4 second exposure. The lights from the dorms at the University of Tampa were just so damn bright that I couldn’t leave the aperture open that long. I like how otherworldly the green looks in the picture when compared to the tones and shades of the objects in the background. It reminds me of a show my old instructor (Mr Tamargo) did way back when I actually took photography.
The last picture I am going to post today is from Houston. Houston has an interesting series of overhead and below ground walkways within the downtown area. Its the kind of thing you usually see in places where the winters keep people indoors. I imagine that the heat drives people inside in Houston. The really strange part of this network of tunnels and bridges is that during the day, downtown Houston looks abandoned, even though there is tremendous bustle if activity going on. I don’t know what the buildings are in this picture but this ring connects the four building at this intersection. I think it looks like an alien spaceship.
Now, in terms of interpretation, I know that photography is interpretative and that the interpretation is at least two-fold. In fact, it was Wah that pointed out to me that black and white photography was abstract art. So, what I mean when I say that digital photography requires interpretation is not that film photography is non-interpretive. I know that the emulsion of film responds in a certain way to light, that this response is not an objective understanding of the scene but rather a kind of interpretation. This is what I think makes photography and art; learning how to use film’s basic interpretative strategy to produce an image that expresses something requires talent and skill. What I think is different about digital film though is that, until the printing process, a single film plane responds one way to the scene. A digital image, because the scene which hits the ccd must travel through a processor before it is displayed can be interpreted differently for different parts of the scene. This, I think, functions more like the human brain, which can compensate for bright spots and dark spots as the image reaches our mind, which allows the human eye to see more range in an scene than a film.
Now, I know about zero of how digital cameras function; I am, to this day, confused about what an ISO for a digital camera could possibly mean. Neither am I that knowledgeable about the biological functioning of the human eye or even the manner in which the physico-chemical signals sent by the eye are interpreted by the mind. So, its entirely possible that I am way the hell off on this discussion. But I like the story I am telling about what is different between the two mediums (film and digital). And, I am really looking forward to hearing what I have gotten wrong about this.
I can’t believe it took me two days to notice this post.
First off I have to be an asshole - did you get one of those new cameras where there is no shutter, just an aperture? ” . . . so damn bright that I couldn’t leave the aperture open that long”
Next, digital ISO. This refers to how much “noise” is in the digital image (try really hard to think of noise as analogous to film grain).
Next, Interpretation. I want to define my terms a little; I assume that we are discussing how the ccd/cmos interprets light as compared to film or the human eye. A digital camera uses a sensor to record light, just like a film camera uses film to record light, and the way I personally “interpreted” your first post was that you felt that the digital camera was interpreting the scene in a way which was similar to the way the brain interprets sensory input from the eye. I’m getting out of my area here, but the way I understand the eye’s interpretation is through use of local versus global contrast with a very quick auto adjusting aperture. In other words, the eye enhances local contrast for us when we are looking at detail keeping all ranges as close as possible inside of what we would call a level with detail still visible, and when we view a large scene the eye adjusts global contrast to yet again keep everything within a range with visible detail (ansel would have said between zone 1 and 9). So, I felt your first post was asserting that your digital camera was adjusting the contrast level to keep detail in the shadows and detail in the highlights (as much as possible).
Now here is where we may run into a disconnect: I assume you are not lumping some post processing software into your definition of “digital camera.” So I am talking about the raw file, or jpeg, or tiff straight from the camera with no photoshop, or cannon image editor (I’m making up names here), or pentax pixel perfect. If you captured the image in raw format there would be the possibility of your file having as 16bit “depth.” And for the purpose of me winning this discussion I am now going to over-simplify bit depth and make it analogous to zones or stops. A standard jpeg has 8bits, and a computer monitor can only display 8 bits, and most color photo paper can only display 8 zones, and ansel taught us that a stop is just like a zone. And while teaching us this he said we should adjust global contrast through processing to compress or expand the tonal range of an image captured on film. Now if we did an N -3 processing of a film with a long toe (I think I am remembering this right, but go get ansel’s book if you want accuracy) you could probably capture over 20 stops/zones/bits of depth. If you wanted to capture more with digital you would have to create a HDR image (which would require some form of post processing).
Digital sensors, just like film emulsions, have a curve when it comes to sensitivity to light. Many digital cameras even replicate the curve of specific films that were popular (e.g. the fuji S3 does this). This curve will effect the contrast of a scene, just like it would for film. So to make a long story short, digital for the most part interprets light in the same manner as film. Where I think you may have came to this conclusion is in the one area where the two differ. Digital cameras do not suffer from reciprocity failure in long night exposures, whereas film does, and compensating for reciprocity failure with film will naturally effect global contrast (again, go read ansel for specifics on this).
First, the status of my camera question. My first response was “no, my camera has shutter” but now I wonder if it doesn’t really have simulated shutter speed. I have a Canon Powershot A610. It is a point and shoot, not an SLR. I haven’t torn it apart nor even delved into the depths of its specs but it does have shutter speeds. One of the reasons I selected this camera over others is that it has the option of manually shooting a picture (ISO, aperture, shutter speed, and even focus). It might be the case that there is no true shutter, instead simply reading the data from the ccd for a certain period of time. The claim I was trying to make there though was that, I wanted to have similar settings as the images in Miami, same ISO, Shutter and Aperture, but the nearby light source was forcing making the foreground so bright that I had to change one of those, I went with shutter speed.
I get the noise thing when it comes to ISO (I should post the night shots I did when there was no moon). But what still confuses me is how that “noise” translates to needing more or less light (for example, the moonless night shots had way more noise at 1600 ISO but the scene was no brighter). I’m just having trouble understanding this concept, I can use it fairly well (Heidegger would claim that I know it); I just want to call it something else.
Your knowledge of photography so completely surpasses mine that I wouldn’t even think about “winning” an argument with you about it. You are right to eliminate the post-process stuff from the discussion; for film we would then have to include printing. I don’t think you are wrong about anything that you said.
I was taking about how the image is when it comes out of the camera (with whatever autofix software turned off). My camera does not, much to my recent dismay, have the capacity to do raw images. The ones posted are the jpegs as they came out of my camera. I guess what impressed me, what led to my initial claims, was the flexibility of digital cameras. And here, the earlier discussion of ISOs comes back. That my camera has some ccd in to which has receptors which read the light and convert into a digital format, is not itself much different than a film camera. But what seems really different is that the digital image on the camera must, it seems necessarily, have gone through some sort of interpretative scheme. The chemical process of film, while interpretive, is a physical process that can only be adjusted by changing the chemical composition of the materials. But the digital camera on the other hand has various ways in which it can interpret the data that is hitting the ccd. I can, for instance, take a picture with 100 ISO or 1600 ISO without changing any part of the make up of the light receptor. What changes is that way the camera interprets that information, or “uses” that information. Likewise, that software can be developed to emulate the curves of various films points to this same occurance (maybe I misunderstand here and the curve is emulated by changing the structure and design of the ccd). Digital images are not direct representations of the light that hit the ccd, unlike film (which, though they present an abstracted view of the scene, are not processed through some interpretative schema [which is funny to say "processed"]), but must be interpreted as part of the conversion process. This is the part that I think functions more like human vision; light hits our cones and rods and is converted into bio-electrical energy and our brain has to interpret the scene. I guess I am saying that film is an interpretation of the scene but that film does not interpret the scene whereas digital images are both an interpretation and interpret the scene. Having said this, I might be conflating two processes within a digital camera and comparing them to one process in a film camera.
there is no such thing as a camera without a shutter, I was just being a smartass, because you said something about how long you left the aperture open, and it isn’t possible to close the aperture (you probably meant to say shutter).
I guess that the ability of digital cameras to auto select ISO is a difference, but it still has to make that selection prior to exposing light to the ccd/cmos. Any raw information captured can only be moved through a range of about four stops, significantly less than the number of stops selection of ISO on a pro dslr can vary exposure (I’m only saying this to illustrate that selections of ISO has to come prior to exposure). I think in the end you are more enamored with your ability to preview your capture in real time and therefore able to capture a more accurate version of the way you envisioned the scene. Because the technology behind auto selection of ISO is no more advanced that matrix metering or ttl in a film camera.
Another thing about the digital camera interpreting data: digital cameras store more information in highlights than they do in shadows, which is why shadow areas are more prone to noise in post processing. I think that this also shows that all of the interpreting is done before the light strikes the sensor, making it in my mind just like a film camera (with the ability to auto change film iso)
You should read this http://www.adobe.com/products/photoshop/pdfs/linear_gamma.pdf it will give you better questions to ask about ISO
“it isn’t possible to close the aperture”
HA! I’m an idiot. I didn’t even catch it when you made fun of me.
I don’t let my digital choose the ISO. I have it set at the lowest setting, which is 100 or something. What initially got me starting thinking down this road was my surprise at just how much information was being recorded at what I thought were fairly short exposure times. The shot of the Biltmore was like 8 seconds and stars show up. I don’t remember getting that kind of density on film. But, it has been a damn long time since I tried anything funky with film.
And I really do like the ability to preview. Immediately knowing if the image came out the way you wanted it is a bonus.
The frickin’ colors are 8,000 feet deep. I ain’t know nothin’ about no apertures, but I’d love to see some street scenes with people in the same kind of “mood” as these.
OH. I fried my brain reading all that photogibberish. I did like the part where Heidigger came into the discussion. HA! Heidigger WISHES he had a digital camera.
I agree with gorjus. The colors ARE 8,000 feet deep.
Also, Houston IS a spaceport, duh.
Oh, yeah. PS. I got the aperture joke.
[Roy, I forgot my password to edit comments! Actually, I put all my old email into a box and dropped it in the sea, so I no longer have it.]
You put your old email in a box and dropped it in the sea? There has to be a story to go along with this statement.
I feel like I’m not getting notices about comments anymore, either that or I am not reading my email.
8,000 feet deep. I like that. I don’t know that I could get any of these with people, unless maybe they were asleep; I think the shortest exposure was 8 seconds. Although, I have occasionally been playing around with doing longer exposures with a flash (something I learned for Roy way back when) in order to fill in the background. I’ll have to see if any of them are worth posting.