One hundred and twelve lines per mm !

Godfrey said:
Lovely lens. I have one too, not in the kind of shape yours is in but it serves. Resolution and contrast have never been a problem.

Minox subminiature lenses are very highly corrected, the most expensive part of the camera. Their resolution is aided by a clamping pressure plate. They can achieve upwards of 200 lp@mm on microfilm, and were used in microdot production by covert services once upon a time. But remember that a 6x8 inch print is already almost a 20x enlargement of the format so it needs that resolution.

The Minox 35GT-E's 35mm f/2.8 lens is also good quality, similar o the 40/3.5 Tessar in the Rollei 35—but not in the same class as the subminiature lenses or the Micro-Nikkor.
Click to expand...
But THE spy camera was the Tessina...

cheers,

R.
 
venchka said:
This is the accepted standard test target. Produced on glass to eliminate changes in size due to temperature variation.
. . .
Click to expand...
Dear Wayne,

The catch to 'accepted' is always 'accepted by whom', and, after that, you have to ask how it was interpreted...

Cheers,

R.
 
Godfrey said:
LOL!
Not according to my buddy from the service, but what do I know? :)
Click to expand...
Not as much as the guys who made Tessinas, which is where I got the story from.

For that matter, one friend of mine in that line of work swore by Rolleiflexes. As he said, "If you're carrying a Minox, you're obviouly a spy. But if you're carrying a Rollei, there's always a chance that you're just a keen photographer. If they catch you and search you, they're going to find it anyway, so what does size matter?" (And yes, I do know how some Minoxes were carried, but I'm told it was not standard practice.)

Of course, it's all unverifiable, in the nature of the business, but it does make for good stories.

Cheers,

R.
 
Roger Hicks said:
Not as much as the guys who made Tessinas, which is where I got the story from.

For that matter, one friend of mine in that line of work swore by Rolleiflexes. As he said, "If you're carrying a Minox, you're obviouly a spy. But if you're carrying a Rollei, there's always a chance that you're just a keen photographer. If they catch you and search you, they're going to find it anyway, so what does size matter?" (And yes, I do know how some Minoxes were carried, but I'm told it was not standard practice.)
Click to expand...

According to my buddy who worked for the state department, the standard espionage cameras at the last gasp of the film era were Nikons with long lenses and disposable point and shoots.

With lens analysis systems and software, a simple, single element, plastic lens could capture amazing amounts of data, cost nothing, and were about as innocent/inconspicuous as you could get.

If Tessinas were the prime tool, well, that's news to me. I had three Tessinas and I wouldn't consider their reliability to be up to snuff for any serious use. The spring-wind mechanisms were particularly fragile and prone to jamming.

They're also somewhat difficult to focus accurately ... the tiny format equipped with a simple ground glass focusing system and slow viewing lens does not make for fast, accurate focusing at close distances. A Minox subminiature with the standard measuring chain can be focused to razor accuracy in the blink of an eye.

digression:
I went to meet my friend at the state department in Washington DC some years ago. Signs all over the place ... "No Cameras or Recording Devices Allowed" ... detectors and a visual inspection of my bag and jacket on entry.

I was carrying my Minox EC in my jeans' coin pocket. I'd completely forgotten I had it. It passed through all the detectors and the visual inspection. I took several photos of my friend in his office ... without even thinking about it.

Now that's a good spy camera. :)

G
 
Thank you for sharing.

I've never paid much attention to lab testing of cameras and lens (though I hope that manufacturers continue to do this to standardize production), and it's good to know the technical reasons;)

If it looks good to me, it's good.

Roger Hicks said:
There is (or was) an astonishingly low degree of standardization, not least because ultimate resolution figures are extremely subjective: they're a matter of edge definition as well as maximum and minimum contrast. Thus, 80 lp/mm with woolly edges can look less sharp than 60 lp/mm with higher edge contrast -- which is one reason you should always treat such figures with deep suspicion.

Perhaps surprisingly, I know more about film resolution than lens resolution, because I've spent more time talking to film manufacturers about it. Kodak and Ilford could never agree, for example. They were very consistent and pretty much interconvertible: they just weren't the same numbers. As far as I recall it was one of the East German universities -- Magdeburg, maybe -- that was reckoned to have the best testing protocols, i.e. the ones that no-one objected to too much.

As for aerial vs. on-film, the few lens manufacturers I've talked to agreed that aerial resolution is all but meaningless, because you can't take pictures on the air. With film, you've got film thickness, flatness and location, and with digital you have Nyquist limits. I know that Zeiss have achieved over 200 lp/mm on film, but they said it took 'focus bracketing', i.e. focusing; shooting, twisting the focus a fraction; shooting again; twisting a fraction more; shooting again; going back to the original mark; shooting again; twisting in the opposite direction...

You also have the mechanical accuracy of the focusing system (including mirror and screen, in a reflex) and the resolving power of the human eye (which is surprisingly variable, even when fully 'corrected').

In other words, with a fine micrometer mount and aerial focusing via a microscope, you can get ridiculously high lp/mm figures, but they're meaningless in the real world. Which is precisely the same as at least 90% of the other things in photography (or indeed, anything else) that are discussed to death on the internet.

The original figures given for the Micro Nikkor are, therefore, of very limited value and are valid only for the R.G. Lewis testing protocol, i.e with a target of given contrast (higher contrast targets give more lp/mm, for obvious reasons) and for a given film which is almost certainly no longer in production. They are of far more interest as an historical document than as any real evidence of the resolving power of the lens. Assuming the lens is still as good today as it was when it was tested, I would be astonished if I couldn't get 125 lp/mm on the right film. But what would it mean?

Cheers,

R.
Click to expand...
 
Godfrey said:
According to my buddy who worked for the state department, the standard espionage cameras at the last gasp of the film era were Nikons with long lenses and disposable point and shoots.

With lens analysis systems and software, a simple, single element, plastic lens could capture amazing amounts of data, cost nothing, and were about as innocent/inconspicuous as you could get.

If Tessinas were the prime tool, well, that's news to me. I had three Tessinas and I wouldn't consider their reliability to be up to snuff for any serious use. The spring-wind mechanisms were particularly fragile and prone to jamming.

They're also somewhat difficult to focus accurately ... the tiny format equipped with a simple ground glass focusing system and slow viewing lens does not make for fast, accurate focusing at close distances. A Minox subminiature with the standard measuring chain can be focused to razor accuracy in the blink of an eye.

digression:
I went to meet my friend at the state department in Washington DC some years ago. Signs all over the place ... "No Cameras or Recording Devices Allowed" ... detectors and a visual inspection of my bag and jacket on entry.

I was carrying my Minox EC in my jeans' coin pocket. I'd completely forgotten I had it. It passed through all the detectors and the visual inspection. I took several photos of my friend in his office ... without even thinking about it.

Now that's a good spy camera. :)

G
Click to expand...

Um... You do know that's why there were non-spring-wind versions available? With ultra-quiet nylon gears? And you've seen the focusing magnifier? And you know you can use a pirce of knotted string with a Tessina in the same way you use a Minox chain? And of course the 14x22mm neg held a LOT more information than 8x11mm.

The US State Department was not the only spy organization in the word. Nor, according to anyone except the US State Department, was it the most efficient. And of course, the idea of a 'standard' spy camera would not occur to most spies...

As I say, none of it's verifiable. But we all have our own sources, A bit like espionage, really.

Cheers,

R.
 
Roger Hicks said:
Um... You do know that's why there were non-spring-wind versions available? With ultra-quiet nylon gears? And you've seen the focusing magnifier? And you know you can use a pirce of knotted string with a Tessina in the same way you use a Minox chain? And of course the 14x22mm neg held a LOT more information than 8x11mm.

The US State Department was not the only spy organization in the word. Nor, according to anyone except the US State Department, was it the most efficient. And of course, the idea of a 'standard' spy camera would not occur to most spies...

As I say, none of it's verifiable. But we all have our own sources, A bit like espionage, really.

Cheers,

R.
Click to expand...

The Tessina does qualify as "a spy camera" but I would hardly call it "the spy camera". In truth, the Tessina is a bit of a Johnny-come-lately.

The Minox qualifies much better for the latter. It was in service for over 2 decades before the first Tessina saw the light of day. It served well in the hands of OSS agents during WWII. The Minox is also so ingrained in common culture that you merely have to mimic the winding/cocking action to carry the message of someone taking "spy" pix.
 
Dwig said:
The Tessina does qualify as "a spy camera" but I would hardly call it "the spy camera". In truth, the Tessina is a bit of a Johnny-come-lately.

The Minox qualifies much better for the latter. It was in service for over 2 decades before the first Tessina say the light of day. It served well in the hands of OSS agents during WWII. The Minox is also so ingrained in common culture that you merely have to mimic the winding/cocking action to carry the message of someone taking "spy" pix.
Click to expand...
No argument there. But equally, don't forget the Kodak matchbox camera, http://www.submin.com/16mm/collection/kodak/index.htm

When I said 'the' I was referring to the discriminating spy who wanted the best before digital took over; somewhat lightheartedly, as you might guess from that sentence.

It's just that the Minox is lazy shorthand for 'spy camera', often used by people who know nothing (or less) about either espionage or photography.

Cheers,

R.
 
Roger Hicks said:
No argument there. But equally, don't forget the Kodak matchbox camera, http://www.submin.com/16mm/collection/kodak/index.htm

When I said 'the' I was referring to the discriminating spy who wanted the best before digital took over; somewhat lightheartedly, as you might guess from that sentence.

It's just that the Minox is lazy shorthand for 'spy camera', often used by people who know nothing (or less) about either espionage or photography.
Click to expand...

Walter Zapp didn't design the Minox to be a spy camera. It just turned out that way. Debating about it is ridiculous :: I suspect that more real spy cameras were one offs than any particular product.

The Tessina lens didn't hold a candle to the post WWII Minox lens. I've used both, extensively, and there is simply no comparison. So saying the Teesina's larger format netted more information is likely just inaccurate. (Yes, I had the focus magnifier and did the measuring chain thing with it too ... The Minox was always a better, more reliable camera to work with.)

But WTH .. Lets get back to Micro-Nikkor 55mm f/3.5 lens lore ... :)
 
I've got a couple of 55 micros. One has a compensating aperture or some such thing. What's that about?
 
Roger Hicks said:
Dear Wayne,

The catch to 'accepted' is always 'accepted by whom', and, after that, you have to ask how it was interpreted...

Cheers,

R.
Click to expand...

Acepted by my father, a USAAF/USAF aircraft commander, and the folks in the photo lab to whom he delivered his exposed film after every mission. Admittedly his missions over North Korea in RB-29s predated the 1951 version of the test chart I linked to. I have a few contact prints from those missions. Alas, I don't have any negatives.
That is good enough for me to accept.
Cheers!

Wayne
 
Back to the Micro-Nikkor 55mm f/3.5 ...

Here are a couple of photos of mine, fitted to a Ricoh GXR with Nikon F to Leica M mount adapter:


GXR-MNikkor55-001.jpg


GXR-MNikkor55-003.jpg


GXR-MNikkor55-002.jpg


GXR-MNikkor55-004.jpg

​

I do have the matched extension tube as well. :)

G
 
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