Preset aperture lenses are different from standard lenses with a single aperture ring and set click stops.
Here’s how they differ, some of the reasons I enjoy using them, and why you should try them too.
First, how they work.
There are different variations, but the feature common to them all is you preset not the exact aperture, but the minimum aperture the lens will stop down to.
There is either via a separate aperture ring, or the main aperture ring is spring loaded and pushes in or out then rotates. This ring dictates the smallest aperture the lens will be at when the main aperture ring is turned all the way in the opposite direction from being wide open.
Here are examples of three minor variants.
With the Helios 44-2, the outermost part of the lens with the red dot is fixed. The next ring in, with the numbers on, clicks to the various standard stops. Above you can see it’s at f/8. The next knurled ring in adjusts freely between the maximum aperture (f/2) and the preset minimum aperture (f/8 in the picture above).
So you can adjust it as precisely as you wish, without needing to be at whole click stops like f/4, f/5.6 and so on. More on why you might want this later on.
The Takumar is similar, but slightly more clear in its design. Again the outermost part with the red dot is fixed. The next ring where you can see all of the numbers sets the minimum aperture, and moves in clicks (and half clicks where you see the white dots). Then the next ring in, also numbered, moves freely between the maximum f/2 and minimum, in this case f/5.6.
The Takumar is a little easier to use for those used to setting an aperture number, as you still line up a specific aperture number with the red dot if you wish to.
The Jupiter-37A has just one aperture ring. Again the outer part with the white dot is fixed. To set the minimum aperture, you push the numbered ring in so its up against the large knurled focus ring, then turn it to the aperture required, then release the ring. It’s spring loaded so it pops back to the rest position as above.
Then the same ring rotates freely between the maximum aperture (f/3.5) and preset minimum aperture (f/5.6 in the picture above).
In practice, choosing and setting the aperture works as follows.
Say you want to shoot a lens at f/8. So you set the preset aperture ring to f/8, then open the lens wide open.
At the lens’s maximum aperture (wide open, so when you look into the lens from the front you can’t see the aperture blades at all), you have maximum light entering, so it’s easiest to compose and focus with the camera.
When you’ve focused, simply turn the main aperture ring all the way down until it won’t turn anymore. Then you know you’ll be at your preset aperture (f/8 in this example) and can take the picture at that aperture.
Preset lenses give photographers a fast way to stop down a lens to a preset aperture, without having to count click stops, or take your eye away from the camera to see where you’re moving the aperture ring to.
Originally preset aperture lenses were superceded by lenses that offered set click stops (at f/2.8, f/4, f/5.6 etc) plus open aperture metering.
With these lenses, you set the aperture ring on the lens but the aperture blades remain wide open (again letting in maximum light for easier focusing) until the instant the picture is taken, at which point they close down to the set aperture via a lever or pin on the back of the lens being depressed by the camera.
But for those of us using film and digital cameras with vintage lenses via adapters, open aperture metering isn’t an option anyway, we have to stop down manually. This is where the preset aperture lens comes into its own.
What I like even more than the convenience of being able to close down in a split second to my preset aperture, is the fine adjustment it allows.
I shoot Aperture Priority (Av) 90% of the time or more. This is because I love to control the depth of field of the image.
Also, because I rarely shoot moving subjects, shutter speed is of little importance to me.
Photographing a decaying door or ancient gravestone or still flower looks exactly the same at 1/30s or 1/4000s.
Varying the aperture though – especially at the close distances I like to shoot at – has a dramatic effect on the final image and its depth of field.
With standard click stop aperture lenses, most have only full or half click stops. The actual number of the aperture I’m using is again pretty irrelevant to when I’m shooting Av mode.
But what if, in terms of the look of the photograph, the depth of field is too shallow at f/4 and too deep at f/5.6?
With a standard click stop aperture lens, you’d have to choose one or the other (or, with some lenses like for example a Yashica ML 50/1.4, you can find the halfway rest point between two click stops).
With a preset aperture lens, you simply turn the aperture ring until the image looks precisely how you want it to.
It’s irrelevant whether it’s f/4.37 or f/5.13. What matters is how it looks.
So, in practice, I often preset my aperture at a stop beyond what I think I will need. Then I have that scope for fine tuning.
For example if I think I’ll need around f/5.6, I’ll set the preset aperture to f/8, then open it up.
After composing and focusing, I’ll stop the lens down until the image I see is exactly as I want it. It might be shade past f/5.6, a little before, or bang on. I have that ability to find precisely what looks most right for me.
And, after all, isn’t that how all of us photograph anyway – point our camera at something then adjust our position and the lens aperture until what we see in the viewfinder is what looks most “right” to us?
Another advantage of preset aperture lenses, is not directly due to their preset feature but seems connected.
My favourite preset lenses tend to have more aperture blades, and ones that close down whilst staying very rounded. The result is smoother bokeh highlights, like this –
With a standard lens, the majority have six blades, and are very straight edged.
So the bokeh highlights look like this –
You can imagine how the first image would have looked it taken with the second lens.
Let’s directly compare two lenses.
The first three images show my Cosina Cosinon Auto 135/2.8 at f/5.6, f/8 and f/11. Notice how the (hexagon) shape made by the (six) blades is already angular at f/5.6 and becomes even more so as you stop down further.
The next three pictures show the Jupiter-37A 135/3.5 at the same apertures – f/5.6, f/8 and f/11. You’ll notice how because of the greater number of aperture blades (12!) and the way they close down, it’s almost perfectly circular, even at f/11.
This smoother, more circular shape makes for smoother bokeh, especially in shots with multiple light sources where each one takes the shape of the open aperture blades in the lens.
Which preset aperture lens(es) I recommend
I love all three of the lenses featured in the first images above and would recommend any without hesitation. The Helios 44-2 58/2, Asahi Takumar 105/2.8 and Jupiter-37A 135/3.5. All are M42 mount and all are fantastic regardless of being preset aperture.
The fact that they are preset lenses just makes them, for me, even more enjoyable and controllable when shooting my preferred Aperture Priority mode.
If you don’t already use M42 lenses, then I recommend getting one of the three above plus an adapter for whatever you do use. It’s probably the most easily adaptable lens mount.
I’ve shot M42 lenses on Contax/Yashica, Pentax K, Canon EOS and Minolta AF film cameras, and Pentax K, Sony NEX (E mount) and Sony a100 and a350 (Sony/Minolta A/Alpha mount) digital cameras. Adapters exist for probably a dozen other camera mounts.
If you’re starting from scratch and want a super affordable film camera set up, check out my recent post on getting started with film for £27.
On the digital front I’d recommend either the Sony a100 DLSR or if you want something more compact and even more adaptable try a Sony NEX 3, 5, or 7. All are amazingly affordable these days.
With a film or digital camera plus an adapter for vintage M42 lenses, preset aperture lenses are a delight to use, infinitely adjustable and give splendid results.
Have you tried preset aperture lenses yet?
Let us know in the comments below.
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