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01-16-2012, 09:10 PM   #1
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A taxonomy of aperture mechanisms

I have a small bureaucratic quandary. For my database, I have need to categorize and describe my lens accumulation, including their apertures. Such categorization is called taxonomy. I use to taxonomize extensively, back in my field botany days. Class, Subclass, Family, Subfamily / Tribe, Genus, Species, Subspecies / Variety, all that good stuff. Naming disputes sometimes led to violence; we'll skip that for now. Be careful not to taxonomize in public, you could get arrested. But I digress.

I have a field in my database structure for aperture type. I'm not satisfied with my own categorization, so I'm asking for help. This taxonomy is what I'm working from:

1) Lenses of any mount:
1a) No aperture mechanism, is always wide-open. This includes pinholes, junk glass, projection-copy-process lenses, mirrors, etc.
1b) Waterhouse stops: holes of various diameters used as stops. Found in some older or stranger lenses.

2) Modified and adapted lenses, including M39 and chopped lenses:
2a) Simple aperture mechanism. Set the f-stop and there you have it.
2b) 1- or 2-ring presets (mostly 2-ring). Set the tightest aperture; spin the dial to wide-open for composition; spin down to the set f-stop for metering and exposure.

3) M42 screwmount lenses:
3a, 3b) Same as 2a and 2b above.
3c) Automatic, M/A switchable. Lens has a stop-down pin and a Manual/Auto switch.
3d) Auto-only. No M/A switch; lens will only stop-down on M42-auto cameras.
3d1) Glued auto-only. The aperture pin is glued or otherwise stuck down.

4) PK-mount lenses:
4a) Same as 2a above.
4b) Presets. I've never seen a PK preset. EDIT: hoanpham tells me of the K28/3.5 shift.
4c) M-type, with mechanical aperture linkage.
4d) A-type, with electrical contacts and mechanical aperture linkage. Includes AF.
4c1, 4d1) Butchered. M- or A-type chopped by Canoneer sadists for their pleasure.

Did I miss any?

The Ap.Type field in my database is narrow. I need to use code words. Ain't no way I'll use (2A) or (3C1) as codes; too opaque. AUTO has too many meanings. MECH and MAN are too general too; M/A and GLUED and 2-RING work OK.

Can anyone suggest anything better?


Last edited by RioRico; 01-17-2012 at 03:54 AM.
01-16-2012, 09:37 PM   #2
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Tax wha'?

QuoteOriginally posted by RioRico:
I have need to categorize and describe my lens accumulation,
Gee, I just call 'em gooder ones, an' badder ones, RR.

I can usually tell 'em apart 'cause the 'badder ones' end up in the bottom drawers, on the dustiest back shelves an' in the darkest closets.

H2

Wha' chu smirkin' for? Ain' no LCS 'round here!
01-16-2012, 10:57 PM   #3
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QuoteOriginally posted by RioRico Quote
4b) Presets. I've never seen a PK preset.
Does this count as a preset? FA 85 soft

Any way to alter the field size in the database?

Where do M42 presets go?
01-17-2012, 12:54 AM   #4
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Maybe not all lenses directly related to aperture linkage, but they may be in a category:

FA soft focus lenses,

Tamron 70-150/2.8 soft focus,
Sample: https://picasaweb.google.com/111102833818394930252/Tamron70_150f28soft

Nikkor DC lenses.

Sony/Minolta 135 STF,

Apodization filter:
Markus Keinath - DIY Apodisation Filter

And perhaps my Petri 28/2.8 which is still sharp but soft wide open, and razor sharp just half click down.
Sample: https://picasaweb.google.com/111102833818394930252/Petri28f28
I use this property before I got the Tamron.

01-17-2012, 01:28 AM   #5
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QuoteOriginally posted by RioRico Quote
Did I miss any?
There are some lenses where you cock the aperture before you take the shot, so you can compose with the lens wide open, and then the aperture stops down when you press the shutter. Rince and repeat. I didn't see this in your list. The very old Takumars used this. Some CZJ Biotar versions also had this mechanism.

QuoteOriginally posted by RioRico Quote
Can anyone suggest anything better?
Some time ago, someone corrected me when I used the term "preset lens" for a Russian lens with 2 aperture rings. Can't remember who it was - stevebrot perhaps? - whoever it was, he had listed better terminology in their answer, but try to find it now if you can. I think the type that you are missing was the real preset.

Let me see if I can remember, it was going something like this, basically looking at both how you set the aperture and how it gets stopped down:
  • Manual aperture would be something like the Industar 50-2 - select does stop down
  • Manual aperture with aperture limiter for manually switching between wide open and selected aperture (the 2 ring mechanism) Helios 44, Mir 1
  • Preset might be the one where you primed the aperture before taking the shot - you prime the lens for a certain aperture, and the camera stops down to it - Old Biotar, old Takumars
  • Automatic was the one where you selected the aperture and the camera stopped down on shutter press (difference from previous is that you don't need to prime the lens for each use) - the later Helios 44 models, Domiplan
  • Then you get hybrids with A/M - the Takumars
  • Last stage would be the ones with camera controlled aperture like the Pentax A series (K and M would fall under auto)

But I think there was some other weird mechanism that I missed here.
01-17-2012, 01:32 AM   #6
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QuoteOriginally posted by pacerr Quote
Gee, I just call 'em gooder ones, an' badder ones, RR.

I can usually tell 'em apart 'cause the 'badder ones' end up in the bottom drawers, on the dustiest back shelves an' in the darkest closets.
My badder ones get sold down the river -- or hidden away until they're worth selling. I haven't had to catapult any yet, but the year is young.

QuoteOriginally posted by jatrax Quote
Does this count as a preset? FA 85 soft
No, it's an AF lens so it's got an electric-auto aperture, and rates a note in the short NOTE field.

QuoteQuote:
Any way to alter the field size in the database?
Not without messing up my screen display. It's already at the edge of visibility.

QuoteQuote:
Where do M42 presets go?
The database has a MOUNT field, which also shows (with a '#') if I've modded the lens mount. So entries might contain:
Yashica ML, type=prime, mount=C/Y#, FL=50, f/1.4-16, aper=man, focus=man, near.focus= 0.5m, iris=8, thread=52mm, 300g, [serial], note=planar, US$10.25, J(apan)

Asahi Tele-Takumar, prime, M42, FL=200, f/5.6-22, aper=2.ring, focus=man, nf=2.5m, iris=10, thread=49mm, 410g, [serial], note=keep, US$21.50, J(apan)
So the TeleTak is M42, 2-ring preset, doesn't focus close, doesn't weigh much, didn't cost much, etc. And the Yashica is modified C/Y mount, fairly heavy, and real cheap. Unusual values get highlighted, so all the 1.RING and 2.RING presets and the BROKE apertures and fast FLs etc show brightly. Alas, the NAME field gets rather jammed with a Wollensak Enlarging Anastigmat, eh?

Anyway, what I'm trying to figure out is a scheme for labeling the various types of apertures that doesn't involve cryptic codes or long strings. Succinct yet readable, from my old poet's training. Maybe I'm having a hard time with this now because I'm pretty feverish. Writing about lenses doesn't take that much brainpower, but building conceptual models does. Ummm, I'll look at the taxonomy above and try this:
N/A = no way to change aperture, like mirrors and magnifiers
WaterH = Waterhouse stops mechanism

MAN = simple manual aperture ring
1.Ring, 2.Ring = presets

M/A = M42 mechanical automation with M/A switch
Auto.O = M42 auto-only, no M/A switch
GLUED = Auto.O with pin secured down

Auto.M = mechanical automation (PK M-type)
Auto.A = electro-mechanical aperture (PK A-type) (includes KAF)
I think|fantasize that these cover the possibilities. But what have I missed? I always miss something until it bites my butt. Especially when I'm brain-dead. Zzzzz...

Last edited by RioRico; 01-17-2012 at 03:50 AM.
01-17-2012, 02:58 AM   #7
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QuoteOriginally posted by RioRico Quote
4b) Presets. I've never seen a PK preset.
Pentax K 28/3.5 shift.
01-17-2012, 05:14 AM   #8
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I think you need to differentiate between K mount with open aperture focusing ( what we now call manual aperture) and true k mount manual aperture where you stop down manually as would apply usually when you swap mounts, but also on lenses like the K500/4.5 where thie aperture is not automatic but it is not a preset.

01-17-2012, 01:46 PM   #9
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QuoteOriginally posted by Lowell Goudge Quote
I think you need to differentiate between K mount with open aperture focusing ( what we now call manual aperture) and true k mount manual aperture where you stop down manually as would apply usually when you swap mounts, but also on lenses like the K500/4.5 where thie aperture is not automatic but it is not a preset.
I assume by "K mount with open aperture focusing ( what we now call manual aperture)" you mean M-type, with the mechanical linkage, and by "true k mount manual aperture where you stop down manually" you mean a no-linkage system as with T2 lenses. I think I'd label the first as AUTO.M and the latter as MAN = simple manual aperture ring. Do these fit? And by preset you mean 2-ring presets, right? I know of at least a couple of 1-ring preset lenses, where the aperture ring is set to a limit but can then be freely spun between wide-open and that limit.

Maybe I'm making too big a thang about this but little flaws in nomenclature just jump out at me when I track hundreds of lenses. If I had more zooms, I'd probably sweat over zoom vs varifocal, IF, 1- or 2-touch, whatever. With apertures, I'm bugged by all the variants I've mentioned. And the relationships between aperture type vs number of iris blades, those seem significant. I think these details are important to understand how the lenses work, what to expect from them, their strengths and weaknesses etc.
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