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Aperture, depth of field, Bokeh and learning aids


Time for an update: I still use film, though. Not vast quantities, but I have a darkroom, and I'm not afraid to use it.

I enjoy every image I take: I hope you'll enjoy looking at them.
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Aperture, depth of field, Bokeh and learning aids

6 Jun 2020 7:55AM   Views : 514 Unique : 369


Modern cameras are like iPads. They will do precisely what you want, fast and with precision. But you really can’t see how the cogs work. This may be one reason why so many photography courses require students to use film – and a reason why the old Zenith cameras that many of my friends had in the Seventies left their owners with a profound appreciation of technical issues. You can see the effect that aperture has on depth of field as you stop down the lens just before releasing the shutter: you can open the back and watch the shutter working.


My pictures illustrate what’s happening: the images of the Zenith with its lens wide open, stopped all the way down to f/16, and at f/5.6 show the aperture blades in use, and give a pretty graphic idea of the effect on the image – full aperture of f/2 lets a lot of light through to the film or sensor. They also show how dusty the lens is inside: I mention this because it has very little effect on performance. A bit of dust in a secondhand lens may be a reason it’s not ‘mint’ and will sell cheaper, but that simply makes it a bargain…


And the iris pictures, shot in my garden (and in my dressing gown and slippers). The one at the top is the ‘Bokeh shot’ – taken with the Helios 58mm f/2 lens from the Zenith at full aperture on a Sony Alpha 7R II. A little below it, and very little different (although maybe the out-of-focus areas are a little smoother) is a shot taken with a Samyang 45mm f/1.8 lens at full bore. Both shots are at the minimum focussing distance for the lenses.


Here is a picture with the Helios at f/5.6: the background is still well out of focus, but there’s much more of the iris sharp. At the bottom of the article, f/16 with the Helios reveals the glamorous back of the garage…


So you have a choice: use a lens wide open for those glowing and vague backgrounds – but be prepared to choose which part of your subject will be sharp. Stop down a bit to ease things, though you will need more care with backgrounds. And stop right down to bring in as much background detail as you can. The differences will all be less pronounced if you step back a bit from your minimum focus distance.


Play with it, the same way that you can with an unloaded Zenith. (And if you’ve got a Zenith, get it out and play with the controls…)


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JuBarney Avatar
JuBarney Plus
12 36 7 United Kingdom
6 Jun 2020 11:01AM
Interesting blog and some lovely iris.
dudler Avatar
dudler Plus
20 2.1k 2048 England
6 Jun 2020 12:15PM
Glad you like both, Ju. It makes it worthwhile doing it every day.

The flowers were in the garden when we arrived here... We've moved them around a bit, but they're reliable. There are some yellow ones further down the garden.

It seemed worth putting together the three elements - depth of field (which is why I use Aperture priority most of the time), Bokeh, and the usefulness of a Zenith... It's so basic, you have to start getting on top of the technical stuff if you use one. And that makes digital simple (providing you don't get caught up in scene modes, layers, and stuff like that!)
AltImages Avatar
AltImages 3 4
6 Jun 2020 9:32PM
Lens iris or flower? Lol

Quote:Interesting blog and some lovely iris.

PaulCox Avatar
6 Jun 2020 10:26PM
This a topic, that I really like, and a lens that I first used when my Brother in Law Wanted to buy a Zenith with the indistar lens so I took him with his sister (now my wife of 47 years) to a camera shop in Bristol and for the same money as the camera with the indistar, I acquired the camera with the Helios a 44-2 he was over the moon. Needless to say from that day on I just think the Helios is a really great lens, which you could blowup a 35mm negative to a 20x16 inch print, and today it reflects in there prices. Another great blog topic. Paul

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