Recently, I was reading up a little on “bright” viewfinders to try to figure out what that was all about. I initially thought it had something to do with the percentage of coverage or the viewpoint, which spec sheets (sometimes) state, but I found out it does not. Once I figured things out a little, I decided to go and do some brightness tests on my own with some of the full-frame digital cameras out there (5D, a900, D700, 5DmII). Here is what I found.

First, here is what the viewfinder specs mean. The percentage of coverage is simply that: when you look through the viewfinder, only the top of the line cameras actually show you 100% of what is actually recorded on the sensor (or film). Magnification, also, is exactly what it says. You will see a figure like 0.72x, meaning the image in the viewfinder is de-magnified just a little. Those do not directly affect the brightness, though.

I also saw a lot about viewpoint. Now this characteristic is no so self explanatory. Basically, this is how far away from the eyepiece/viewfinder your eye can be and still see all of the image in the viewfinder. And for folks like me who wear glasses, that actually is important. The bigger that number, the less of a chance I have of needing to crush my glasses in between the camera and my face just to see everything. As you can see, though, this has little to do with brightness either.

Then, I found a handy article about viewfinder brightness on Luminous Resource. The examples were all film cameras, which would be really hard to actually pick up and compare these days, as the article suggests we do, but the principles are still the same.

Basically, brightness is related to the focusing screen. The light comes in the lens, bounces up off the mirror, goes through the focusing screen, bounces around in the pentaprism, and then out to your eye. Focusing screens can be bright or not, and it has some affect on focusing, though in the super fast auto focus world of today, I could not really figure out from the article what the affect on focusing is with modern day focusing systems.

Anyway, the long and short of it is this: there is no measurement for brightness. You just say, “wow, that’s bright” or “look’s good to me” and buy your camera. It does make a big difference, though. The darker the situation, the more a bright viewfinder, the more you will still be able to see.

Ok, field tests. Since there is no measurement and you really just have to compare, that is exactly what I did. I will cut all bias out and just give you the facts of what I compared.

Sony a900 vs. Canon 5D
At first, I looked around in one camera, then the other (in the same environment, same store). The Sony seemed brighter. Then, I got the (maybe not so) bright idea to put one camera up to each eye, looking through both at the same time (at which point I got some interesting looks). The Sony was WAY brighter than the Canon. There is my measurement…”WAY” brighter.

I do not know how much the lens on the camera can affect this, but both cameras had the high quality zoom kit lenses. So, they were on pretty even ground. And aperture should not be an issue, because the lens aperture stays wide open till the time a photo is taken, at which point it will quickly close down to your setting and return to fully open, and both these lenses have approximately the same aperture.

Canon 5D vs. Nikon D700
What I was missing was the D700 (this was before the 5DmII was out). So, on a different occasion, I was able to do the same comparison, one camera up to each eye. I could not tell a difference between the Canon 5D and the Nikon D700. Well, they did seem different, but it is so subtle, that if the brightness is different, it is very close. As for lenses (if it matters), the Canon had the f/4 kit lens, and the Nikon had it’s kit lens on too. At least, I am pretty sure…it might have had my f/2 35mm on there…but I do not think so.

Canon 5D mark II vs. Sony a900
Then, the Canon 5D mark II came out. I expected it to be the same as the original 5D, but when I had a chance to try it out against the a900, the results surprised me. I could not tell a difference between the Sony a900 and the Canon 5D mark II viewfinders’ brightnesses. Again, it seemed different, somehow, but I could not definitely say which one was brighter. It was more like a slight difference in tint more than one in brightness. This time, the Canon had the f/4 kit lens on and the Sony had an f/1.4 50mm on there. So, if lens and aperture do play some part, then the Canon 5D mark II wins.

Conclusion
I am no expert, but since the experts will not give us conclusive tests, I have to do my best when judging viewfinder brightness on my own. It looks like the Sony a900 and Canon 5D mark II are brighter than the Nikon D700 and Canon 5D, though those have not all been compared against each other or all compared in the same environments. Short of a mega photo store, I cannot make a better comparison. I am lucky they even let me touch some of those, much less try to find all four in one store at the same time.

Now, I do not want to say anything bad about the Canon 5D or the Nikon D700. I have had two professionals (one of whom I very much trust and has a lot more experience than I do) say they loved the bright 5D. So, assuming my comparisons have some validity, they have much to look forward to in the Mark II.

I would take any of them…though that Sony had an awfully loud shutter, less of a click and more of a clump, if you know what I mean. And feel free to leave your comments below. Do you think I am full of it? Do you know more than me? Tell us all…my pride is certainly not based on my ability to judge camera brightness. I am learning here too.