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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9 Oct 2020 9:15AM   Views : 460 Unique : 291


I’ve been reading Private Eye for around 30 years… My predecessor in a job I held for just short of ten years recommended it over all the public sector and finance magazines for finding out what’s going wrong in local government (which is why internal auditors read the press! We want to get advance warning of investigations we may get involved in…)

There’s a column in Private Eye called Pedantry Corner, reserved for readers who wish to make pedantic points: and I’ve latched onto one of these, about the distinction between ‘practise’ and ‘practice’. Not just alternative spellings, wrote Dr Julian Marsden, though I had to resort to my two-volume Oxford Dictionary, rather than my Sixties single-volume Chambers.

With a C, the word is a noun: a doctor is a partner in a GP practice, for instance. But if you want to achieve perfection, you need to practise. Now, I’m pretty sure, grammar and spelling pedant as I am, that I had missed the distinction for my sixty-something years. Sorry: I know that I use the word a lot, so I apologise to everyone in the Critique Gallery who I’ve ever advised to ‘practice as much as you can’ – I apologise.


It’s a little bit like the difference between depth of field and depth of focus. Do you know the difference?

Depth of field is the one we talk about more: it’s the range of distances from the camera that are sharp with any given lens at any given aperture. Depth of focus is the amount that the film or sensor can be moved without losing acceptable sharp focus. So ‘field’ is in the landscape in front of the lens: focus is inside the camera where you do the focussing.

Does any of this matter? Much of the time, you’ll get away with imprecision. And one day, it’ll wreck your plans and your pictures. For instance, precise focus matters in low light - the images of Princess Bee and particularly the head shot of Eviee, both in low light, one with a Lensbaby, the other with an 85mm f/1.4 lens at full aperture: not so much with the image of Rugeley power station waiting for demolition, in broad daylight. The first two rely in very limited depth of field.


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dark_lord Avatar
dark_lord Plus
19 3.0k 836 England
9 Oct 2020 12:36PM
Spellings and meanings change over time, though there are more important aspects of grammar and words that are incorrectly used. That's why so many foreign people are better at English than some native English speakers.
But as for technical terms such as the depth of field and depth of focus which are completely different there's no excuse. To use a car analogy, as I know you'll appreciate, it's like the difference between petrol and diesel.
GGAB Avatar
GGAB 7 31 1 United States
9 Oct 2020 12:37PM
So, showing my inexperience here, how do you move the film or sensor inside the camera?
Is "Depth of Focus" something that is actually used by the photographer or a specification used by Camera Design Engineers?
chase Avatar
chase Plus
18 2.5k 682 England
9 Oct 2020 1:13PM
I am going to have to read this several times, interesting the difference between DOField and DOFocus.
I think I get it Wink
mistere Avatar
mistere Plus
10 37 8 England
9 Oct 2020 2:22PM
Farmers produce produce?
The tip was full so they had to refuse more refuse?
The dove dove into the trees?
I object to holding that object?
The bandage was wound around the wound?
At least ‘practise’ and ‘practice’ have a different spelling. I had no idea that the film or sensor could be moved to
effect the focus. It makes sense that moving them would do that but i thought focusing was done with the lens.
Every day's a school day SmileSmile
dudler Avatar
dudler Plus
20 2.1k 2048 England
9 Oct 2020 4:46PM
That's a interesting collection of comments!

George - depth of focus is only controllable in design and manufacture, but it really matters that it's done well. It's why film camera pressure plates differ so much, and why some cameras have quite odd film travel paths. The ultimate example, I think, was the Contax RTS III, which had a vacuum mechanism to hold the film against the plate - almost every other camera presses the film against a frame and hopes for the best. I'm aware of a couple of Rollei twin lens reflexes that had a glass plate in front of the film and a metal pressure plate behind it - this should control the problem that film cam bend forward in the middle of the frame.

A sort-of related issue is that any focus mechanism except on-sensor types in mirrorless cameras assumes the film/sensor is where it should be. Earlier upper-bracket DSLRs could be adjusted so that the sensor was in precisely the right place to match the AF mechanism, and later models allow calibration with individual lenses. Depth of focus matters to all of us, in the same way as the firing sequence of the cylinders in our car engines does. Usually, it's under the bonnet and doesn't come to attention...
Jestertheclown Avatar
Jestertheclown 14 8.8k 255 England
9 Oct 2020 8:40PM

Quote:‘practice as much as you can’

Good advice.

(Not advise!)
dudler Avatar
dudler Plus
20 2.1k 2048 England
9 Oct 2020 9:06PM
Though it should, I submit, be 'practise as much as you can'...
Jestertheclown Avatar
Jestertheclown 14 8.8k 255 England
9 Oct 2020 10:35PM
It should; I hadn't noticed that . . . !

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