Digital Photography from 20,000 Feet
by Wesley Fink on September 25, 2006 12:05 AM EST- Posted in
- Digital Camera
Shutter Speed: Stopping Motion and Controlling Light
Shutter speed is technically how long the the shutter remains open in a digital SLR or any camera. This is only theoretically the case in SLRs since a focal plane shutter uses a moving slit to expose, but it is close enough for our discussion about photo basics. There is an old rule that any photographer, even an amateur who doesn't care about understanding the process, needs to commit to memory. We will make it bold.
The fastest shutter speed you can hand hold is 1 over the focal length of the lens.
What this means is the fastest blur free picture you can shoot is at a shutter speed of one over the effective focal length of the lens. This means our 18-55mm lens, which acts like a 28-85mm lens can produce sharp pictures at 1/30 second or faster at the wide-angle end and 1/125 second and faster at the telephoto end. Some people are really good at holding a camera steady and can do better than this, but this is always a good rule of thumb.
The shutter speeds for a digital SLR are much wider than you will find on a point-and-shoot digital. Where the point-and-shoot might do 2 or 3 speeds up to 1/600s, the digital SLR offers a very wide range of shutter speeds. Most SLRs today perform over a range of about 30 seconds to 1/4000 second, and the shutter speed range is similar to ISO in that the larger the number the more light is passed. The scale is also approximately linear:
1 - 1/2 - 1/4 - 1/8 - 1/15 - 1/30 - 1/60 - 1/125 - 1/250 - 1/500 - 1/1000 - 1/2000 - 1/4000
Each value going faster passes half the light of the lower value. So 1/15s passes twice the light of 1/30s. This brings us back to the other part of why you get blurry pictures with your kit zoom lens indoors. Since the kit zoom passes 1/4 to 1/12 the light of a normal f1.7 lens, it must shoot at slower speeds (let in more light) for proper exposure. When you fall below 1/60 to 1/30s those properly exposed images will be blurry with your kit zoom.
Shutter speed is technically how long the the shutter remains open in a digital SLR or any camera. This is only theoretically the case in SLRs since a focal plane shutter uses a moving slit to expose, but it is close enough for our discussion about photo basics. There is an old rule that any photographer, even an amateur who doesn't care about understanding the process, needs to commit to memory. We will make it bold.
The fastest shutter speed you can hand hold is 1 over the focal length of the lens.
What this means is the fastest blur free picture you can shoot is at a shutter speed of one over the effective focal length of the lens. This means our 18-55mm lens, which acts like a 28-85mm lens can produce sharp pictures at 1/30 second or faster at the wide-angle end and 1/125 second and faster at the telephoto end. Some people are really good at holding a camera steady and can do better than this, but this is always a good rule of thumb.
The shutter speeds for a digital SLR are much wider than you will find on a point-and-shoot digital. Where the point-and-shoot might do 2 or 3 speeds up to 1/600s, the digital SLR offers a very wide range of shutter speeds. Most SLRs today perform over a range of about 30 seconds to 1/4000 second, and the shutter speed range is similar to ISO in that the larger the number the more light is passed. The scale is also approximately linear:
1 - 1/2 - 1/4 - 1/8 - 1/15 - 1/30 - 1/60 - 1/125 - 1/250 - 1/500 - 1/1000 - 1/2000 - 1/4000
Each value going faster passes half the light of the lower value. So 1/15s passes twice the light of 1/30s. This brings us back to the other part of why you get blurry pictures with your kit zoom lens indoors. Since the kit zoom passes 1/4 to 1/12 the light of a normal f1.7 lens, it must shoot at slower speeds (let in more light) for proper exposure. When you fall below 1/60 to 1/30s those properly exposed images will be blurry with your kit zoom.
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feraltoad - Monday, September 25, 2006 - link
Is providing a single sentence regarding start-up time dwelling? I don't think any camera review is complete without listing startup times and listing shot to shot time. I think it's a bit hypocritical to focus on core architecture, timings and such and then say a length of time I can actually perceive is not relevant. Especially, when you go and provide such a good article. I think you are just trying to make the other review sites seem stodgy and backward or just wrongheaded, and show that AT is "with it". Moreover, you say they speak gibberish like they are jargon slinging photo elitist snobs. Then you provide,IMO, a pretty techical primer, when they probably have some material for novices too. I know you were just saying "We're Cool, We Rule!", but I don't think when ur AT you have to do that. AT is already in my RSS reader because it does quality reviews. I just skimmed the article, and I can't wait to go back and read it in depth. I'me really excited about AT doing photo stuff too. I agree with the above poster that finding some standard meaningful benchmarks with good subjective commentary will have AT ruling the roost in camera reviews. Not to plug another site, but I think Steve's Digicams provides excellent reviews, actually his site is about the only site I really find useful for cameras. I'm glad I will soon have two sites that provide good information. YAY AT!soydios - Monday, September 25, 2006 - link
How does AnandTech review and compare its computer components? With standardized benchmarks and editorial commentary. Compare all the cameras with a good, strong set of standardized tests across the board, and also add a dose of the editorial commentary.In particular, for the sub-$1000 market, I would suggest evaluating the kit as a whole (image quality with kit lens). Personally, I will be picking up a Nikon D50 with the 18-55mm and 55-200mm lenses, and I have researched the heck out of that package, trying to find an AnandTech-esque review.
Venturing above the sub-$1000 (although I would be very intrigued by some reviews of the professional-level equipment) would get very expensive very fast. Perhaps start small, then venture into the almost-pro market (Nikon D200 and Canon EOS 30D, and some of the $500-$1000 lenses), then maybe dip a toe into the professional level, just to let us all see what the real fancy stuff is like (since very few of us will be buying a D2Xs or EOS-1D MkII-N).
Time permitting, I would put out some quick looks at the Nikon D50 and the Canon EOS 350D, with some comparison between the two. A review/comparison of both the Nikon D80 (in the works, good!) and the Canon EOS 400D would be an interesting read.
Again, review the D-SLR market the same way you guys do computer hardware. Avoid the slugfest low-range and the stratospherically-priced high range. Focus on the high-midrange market (the sub-$1000 D-SLR's to start, move up to the $1k-2k market once you gain some feel for differences between cameras). Do across-the-board standardized benchmarks, with some synthetic but more real-world results.
mostlyprudent - Monday, September 25, 2006 - link
Exactly my thoughts. I have spent some time at a number of camera review sites and am always left wondering "Is the Nikon D80 good enough to justify the price difference over the D50?". "What about the Canon EOS 30D? How much better is it then the Nikon D80 or the Rebel XT/XTi?"Maybe these cannot be answered in the same way as CPU and GPU articles, but standardized tests and comparisons would be nice.
Give me some numbers! I don't want to hear "shot-to-shot performance was sluggish compared to higher end cameras"...unless you can quantify that for me.
Lighting is such an improtant part of photography. Standardized indoor lighting under a couple different kinds of lighting situation (i.e. low, bright, fluorescent, etc.). I don't know how to standardize outdoor shots, but it sure would be nice.
bigpow - Monday, September 25, 2006 - link
I'm gonna stick with www.dpreview.com for now if I want to get my digital photography news/articles.AT, stick with PCs, will you?
silver - Monday, September 25, 2006 - link
I don't understand as I usually read more than one site on one subject. For instance I've been reading Tomshardware since it was sysdoc.pair.com and both Anandtech and Extremetech nearly as long.jnmunsey - Monday, September 25, 2006 - link
Geez, you'd think a site like Anandtech would find someone who knows what he's talking about to write this article...soydios - Monday, September 25, 2006 - link
I'm just a photography hobbyist, but I thought that the article covered all the important basics of full-manual general photography and digital photography.I would touch on filters, though. Those can come in handy. Particular onces to focus on: UV ("does it actually do anything, or is it just a lens protector?" debate), Polarizing, and the primary colors (blue, yellow, and red).
soydios - Monday, September 25, 2006 - link
Concerning polarizing filters (I really wish there was an edit functionality for comments): circular polarizing works with autofocus and digital cameras, linear does not.I know AnandTech isn't much of a software website, but a short article on editing software (Adobe Photoshop, beta of Adobe Lightroom, Apple Aperture) would complete the picture. No need to focus on the software or printing, but a photography software article written in the same manner as this one is something that would help me a lot! (I have almost no experience with editing software).
Wesley Fink - Monday, September 25, 2006 - link
We all want to improve, so please provide specifics so we can address them. It would also be helpful if you would provide your photography credentials, so we can know the level of expertise to attach to your comments.kilkennycat - Monday, September 25, 2006 - link
... a first-class and technically-meaty summary of the current status of digital camera technology. Well up to the usual Anadtech standards. Congratulations, Wes. The addition of a Digital Camera section is a superb idea. By all means, use reference charts, lighting and scenes for resolution, optical-distortion, shading and color-fidelity comparison of both lenses and sensors. Just as you have with video cards and CPUs, come up with your own benchmarks if necessary.