The Camerapedia definition does not specify that the motor or spring is required to return the mirror, just that the end of the shutter cycle triggers the mirror return, which is what happens on all the motor driven cameras (except maybe the Hasselblad EL's, which requires you to release the shutter button to trigger the mirror return).Not at all. The definition in the given wiki link is quite correct. When your thumb (or the built-in motor) is required to reset the mirror then this cannot be considered an instant-return mirror any longer.
I prefer to leave my camera shutters untesioned/unwound. I have a thing about keeping spring loaded things tensioned unnecessarily. Plus some of these old cameras do not have a shutter button lock....My own viewpoint is that an instant return mirror is one of the least useful features to be found on SLR cameras...
...but I would be interested to know what other people think about this issue.
I prefer to leave my camera shutters untesioned/unwound. I have a thing about keeping spring loaded things tensioned unnecessarily. Plus some of these old cameras do not have a shutter button lock.
The other thing that I like is to be able to change the lens when the camera is uncocked for the same reason above. The only cameras where this is an issue is Hasselblad V's.
But that does not stop me from using Hasselblads, or Pentacon-6's etc... It's just a preference.
I realize Hasselblad advertised that, but that was out of design necessity - and they made sure the springs were of high enough quality to last a long time. But that doesn't change the fact that an untesnioned Compur main spring lasted longer than a tensioned one. And they did upgrade their main springs on the CFi lenses to make them last even longer. It's just my old school/engineering background that makes me store my cameras and lenses untensioned when possible.However Hasselblads were specifically designed to be stored with the shutters cocked. The lens springs are supposed to be tensioned.
sounds more like a TLR than a RF. Non moving mirror, leaf shutter, bright and sharp viewfinder. ... IDKHere we go again with the nasty fake news spread by RF people who are just plain jealous of SLR owners. Get over it and buy an slr.
Is there a list of such MF cameras?
Hasselblad driving by electric motors
A lot of helpful people have tried to assist. Perhaps you might put yourself out enough to elaborate on exactly what you are asking about, and why. Less aggravating for everybody that way.This is not the instant-return mirror feature I'm asking about.
Sorry, I missed that fact. You must have cited a reference, study, metallurgical paper, etc. Didn't see it. I did see you express an opinion (above). I'm not saying you are necessarily wrong. Simply that your opinion doesn't meet my own understanding of what the word "fact" means. It is an interesting topic. If you can provide some solid reference about cocked v uncocked I'd be grateful.I realize Hasselblad advertised that, but that was out of design necessity - and they made sure the springs were of high enough quality to last a long time. But that doesn't change the fact that an untesnioned Compur main spring lasted longer than a tensioned one. And they did upgrade their main springs on the CFi lenses to make them last even longer. It's just my old school/engineering background that makes me store my cameras and lenses untensioned when possible.
So, I ponder why. of every camera I've ever used, my Hasselblads have the most convenient easy to use mirror pre-release button? I agree with you. But at least with a 'blad it's easy to take the mirror out of the equation.Here we go again with the nasty fake news spread by RF people who are just plain jealous of SLR owners. Get over it and buy an slr.
I realize Hasselblad advertised that, but that was out of design necessity - and they made sure the springs were of high enough quality to last a long time. But that doesn't change the fact that an untesnioned Compur main spring lasted longer than a tensioned one. And they did upgrade their main springs on the CFi lenses to make them last even longer. It's just my old school/engineering background that makes me store my cameras and lenses untensioned when possible.
A lot of helpful people have tried to assist. Perhaps you might put yourself out enough to elaborate on exactly what you are asking about, and why. Less aggravating for everybody that way.
Sorry, I missed that fact. You must have cited a reference, study, metallurgical paper, etc. Didn't see it. I did see you express an opinion (above). I'm not saying you are necessarily wrong. Simply that your opinion doesn't meet my own understanding of what the word "fact" means. It is an interesting topic. If you can provide some solid reference about cocked v uncocked I'd be grateful.
Cheers
Brett
I figured that I'd get some grief form that statement after I posted it. It's getting off topic, but it's been 3 page, and we've already wandered off topic on mirror per-release... but I'll try to be brief.Not only are the advertised to be stored cocked, they were designed to be stored cocked. I would rather trust knowledgeable people than take advise based on what someone had for breakfast.
A naive question about limits: Is there a relationship between fatigue limit and elastic limit for a material?I figured that I'd get some grief form that statement after I posted it. It's getting off topic, but it's been 3 page, and we've already wandered off topic on mirror per-release... but I'll try to be brief.
I am not going to provide any reference documents because I no longer have them, it was back in the paper days. You can do your own research.
From an engineering stand point, tensioned springs are under higher stress than untensioned. The Compur and Prontor springs are 4 turns, and they get tension over 270 deg. That is significant, and the strain is beyond the fatigue limit, which is why they eventually fail. Standard engineering practice is to leave springs untensioned, which makes them last longer.
Hasselblad and Zeiss introduce the upgraded Nivarox main spring to increase the lifetime on their CFi lenses. In an interview article (back then), they talked about the change, and the "engineer" mentioned that untenstioned springs last longer (which is standard engineering knowledge on springs that exceed the fatigue limit).
But as I said before, that does not mean you should keep your Hasselblad equipment untensioned. The product's "designed life time before service" was calculated in a tensioned state, which is why they used a quality spring. As Sirius said, they were "designed to be stored cocked". However, the product is likely to last longer than the "designed life before service" if you take some simple engineering care when stored. Some of that equipment is 50 year out, likely beyond the design life.
I will give an analogy - aluminium has no fatigue limit - Zero! That means it will break if you cycle it under stress enough times. So how do all those aluminium stress structures survive? (Planes, bikes, car suspensions, etc...). The product is designed to survive X number of load cycles, which exceeds the number you expect for the life of the equipment. In other words, it lasts your/its lifetime. The Prontor main springs are designed to last X number of cycles - I don't have the # of cycles because Zeiss did not publish that (at least not when I looked, but its just like the shutter cycles quoted on SLRs, which are partly based on the calculated lifetime of their main spring). Strain (tension on the spring) and load cycles are well understood in materials engineering, so I prefer to store all my precision spring loaded equipment untensioned. That does not mean you have to. Because Hasselblad's design and quality (and service) on their V series was so good that a lot of the equipment is still functional.
PS: I had french toast for breakfast...
The metal levers on the earlier ETR series cameras fit perfectly on the ETRSi in place of those accursed plastic levers.P.S. if you want mirror lock up watch out for the "Si" Bronicas the last versions, ETRSi and SQAI have plastic levers for the mirror lock and multiple exposure. Twice I've had the plastic levers break. Design flaw in a molded plastic part. I ordered a scrap body for parts.
That's good to know, I have a SQA as is body on it's way I'm going to fix my last SQAi body .The metal levers on the earlier ETR series cameras fit perfectly on the ETRSi in place of those accursed plastic levers.
Is it so important to have an instant return mirror in medium format anyway? You're never going to be machine gunning with them...
Not only are the advertised to be stored cocked, they were designed to be stored cocked. I would rather trust knowledgeable people than take advise based on what someone had for breakfast.
Is it so important to have an instant return mirror in medium format anyway? You're never going to be machine gunning with them...
I should add that the metal levers are not directional, so they can be used used in place of both the mirror lockup lever or the multiple exposure lever.The metal levers on the earlier ETR series cameras fit perfectly on the ETRSi in place of those accursed plastic levers.
I doubt most of us shoot this way, but...
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