July 8, 2021
#428
Gentle reader,
For many DECADES a "normal" camera lens, one with a "view" similar to what we see with our eyes was considered around 50mm or two inches for REALLY old cameras.
However, in the digital camera world, with different sizes of sensors, the question is not so easily answered.
For an example, here is a quote from a more in-depth article on the subject:
"To not get into the slippery territory of dogmatic equivalence, focal lengths in this article refer to 35mm film. So your Olympus 12mm F2 for Micro Four Thirds is a 24mm. The Canon 50mm F1.2L is what it says, a 50mm, but only when mounted on a “full-frame” 35mm sensor. On a Rebel/Kiss the 50mm becomes a longer 80mm." *
I don't recall where I found this chart. But it clearly shows the different sizes of many digital sensors and their size in millimeters. The BLUE frame around each sensor is 35mm full frame for comparison's sake.
Most DSLR cameras (Canon being the exception) use APS-C sized sensors. Which have a "Crop Factor" of 50 percent.
What that means is a 50mm lens on an APS-C sized (not full frame) DSLR has the "angle of view" of a 75mm lens on a 35mm film or full frame digital SLR camera, not 50mm.
Nikon, and Pentax are, to my knowledge, the only camera makers that maintained their camera mounts from the late 1950's until now.
So, if I still owned it, I could mount the Nikon 28mm lens (above) from the 1960's on my D300, and in Manual mode make images with it just fine.
This is one of MANY 35mm rangefinder cameras I once had in my collection. NOTE that the lens is 40mm, not the 50mm so often associated as a normal lens for 35mm.
This is a Yashica Lynx which houses the fastest fixed lens (not removable) lens with a maximum aperture of f1.4. "Fast" in this case refers to how much light the lens will let in when the aperture is fully open. Note that it is a 45mm lens.
This image is of the back, or film/sensor, side of camera lenses. The leftmost lens is a 50mm f1.5, the next two are f2.0 and the one on the right is f3.5. As you can see, the higher the number, the smaller the opening or "exit pupil" of the lenses is. Thus, when the aperture is wide open, the one on the left lets in MUCH more light than the one on the right.
The previous photos of lenses and cameras, all 35mm, mounted with "normal" lenses were for illustration purposes as to various camera makers idea of a "normal" lens.
The two photos above show the three "prime" lenses I bought for my Nikon D300 digital SLR camera. Prime means ONE focal length, and NOT a zoom lens.
The 35mm lens, being strictly digital, has by default the aperture closed all the way. So, I had to hold it open to show the f1.8 opening which is identical to the 50mm lens.
The following three images were shot in my home office while I stood behind my desk. No flash was used, the reflected light is from the ceiling light fixture.
This was shot with the 28mm lens.
This was shot with the 35mm lens.
And this was shot with the 50mm lens. Now, as I mentioned, the 50% "crop factor" changes the angle of view of film lenses when mounted on non-full frame Nikon digital SLR cameras.
Thus, the first photo, shot with a wide angle 28mm lens is the angle of view of 42mm on full frame or 35mm film. On the wide end of "normal".
The middle photo shot with the 35mm digital lens equates to 52.5mm. On the long end of "normal".
The bottom photo shot with the 50mm lens is equal to 75mm on 35mm film or full frame digital, which is the beginning of telephoto lens' view.
As you can see, it has a Leica Vario-Summilux lens which is equivalent to 24-90mm on full frame or 35mm film. And the lens has the same f1.4 maximum aperture of the huge 45mm lens on the Yashica rangefinder camera. Even at 90mm, it is still a quick f2.3 opening. I LOVE this camera!
Now, of course, the "kit lens" on most consumer Nikon DSLR cameras is the 18-55mm zoom.
And, the aperture gets SMALLER (f5.6) as you zoom out, which means LESS light is getting in requiring a SLOWER shutter speed.
So, what have we discovered here? That there is no "normal" lens, really, when compared to what our TWO eyes see.
The article I referenced at the beginning of this article is linked below:
As I mentioned above my distaste for "variable aperture" lenses, such as the Nikon 18-55mm, I was fortunate to obtain a special Lumix camera which has a Leica zoom lens which has a CONSTANT aperture of f2.8 from the wide (25mm) end all the way to 600mm!
"What? That's impossible," you may be thinking. But it is true. If any company could pull that off, it is Leica. Mine is a Lumix DMC-FZ200. The FZ300 also uses the same lens.
This is zoomed all the way out to 600mm! That's my car. The compression of long lenses makes the neighbor's truck appear to be close behind my Volvo wagon, but it isn't.
Getting back to the first image of this article, which shows digital camera sensors compared to full frame. My two Lumix cameras, while both having impressive Leica lenses, have TINY sensors. They have one of the three in the bottom row.
Compare their size to the APS-C two rows up and the Nikon sensor while having similar pixel count, has LARGER pixels which means less "noise" in the images.
Below is my D300 wearing each of the three lenses shown above and used to shoot the wall opposite me.
Note how far back in the lens' body is the 50mm front glass element compared to those of the 35mm and 28mm lenses.
All three digital cameras I own have their uses. The FZ200 is MUCH lighter than my D300 and there does not exist a 25-600mm lens which I could mount on it. If there was one, it would require a hand-truck to move it around! The LX7 I mostly use for creating images for this blog and selling on eBay. It is compact enough to fit in a cargo pants pocket, when going out.
For related articles here are some more links:
Thank you SO much for reading my humble blog. I hope that you enjoyed reading it and perhaps learned somethings as well.
Scott
July 8, 2021
#428
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