mirror placement
Nov 8, 2015 08:44:38 #
srron
Loc: Courtice,On.
This has probably been thought of already, but I wonder if it would be feasible to place the mirror on the front of the shutter curtain thereby eliminating the swing away mirror.
Nov 8, 2015 08:55:10 #
I'd like to see the engineering that it would take to do that, cameras are big enough already...
Nov 8, 2015 09:06:38 #
The mirror is at an angle to reflect light up into the pentaprism. If it was on top of the shutter, how would it reflect the light to the eye piece? Seems like it would reflect the light back out through the lens in this case...
http://dev.m.actasdermo.org/imatges/403/403v103n06/grande/403v103n06-90153267fig1.jpg
http://dev.m.actasdermo.org/imatges/403/403v103n06/grande/403v103n06-90153267fig1.jpg
Nov 8, 2015 09:21:26 #
RWR
Loc: La Mesa, CA
srron wrote:
This has probably been thought of already, but I wonder if it would be feasible to place the mirror on the front of the shutter curtain thereby eliminating the swing away mirror.
You need not worry about someone beating you to the patent office.
Nov 8, 2015 09:41:11 #
Everything new is old! Used one of these for a while long ago.
http://camerapedia.wikia.com/wiki/Canon_Pellix
http://camerapedia.wikia.com/wiki/Canon_Pellix
Nov 8, 2015 10:25:03 #
quixdraw! That's the pellix and I hate that but I think the OP is talking about something else.
I hate the Pellix because it robs light to feed the viewfinder and as you know a stop of light is worth a lot of money. And the viewfinder is not as bright as the one with a regular mirror.
I hate the Pellix because it robs light to feed the viewfinder and as you know a stop of light is worth a lot of money. And the viewfinder is not as bright as the one with a regular mirror.
Nov 8, 2015 10:30:38 #
BebuLamar wrote:
quixdraw! That's the pellix and I hate that but I think the OP is talking about something else.
I hate the Pellix because it robs light to feed the viewfinder and as you know a stop of light is worth a lot of money. And the viewfinder is not as bright as the one with a regular mirror.
I hate the Pellix because it robs light to feed the viewfinder and as you know a stop of light is worth a lot of money. And the viewfinder is not as bright as the one with a regular mirror.
Wasn't one of my favorites. Used it as a stopgap for 3 or 4 months before I got into Nikon. Got some good pictures with it though.
Nov 8, 2015 11:04:56 #
srron wrote:
This has probably been thought of already, but I wonder if it would be feasible to place the mirror on the front of the shutter curtain thereby eliminating the swing away mirror.
Wouldn't that add weight to the shutter curtain thus slow down shutter speed?
Nov 8, 2015 11:26:08 #
Mac wrote:
Wouldn't that add weight to the shutter curtain thus slow down shutter speed?
Exactly! This excerpt from THIS ARTICLE about the titanium shutter with the honeycomb pattern of Nikon's FM2n, FE2 and FA which helped increase speed to 1/4000th sec. A benchmark for 1982.
"Because, to increase the shutter speed to 1/4000 second, it was necessary to reduce the traveling mass of the shutter curtains. Titanium was chosen, because it has a low specific gravity."
Nov 8, 2015 13:21:05 #
quixdraw wrote:
Everything new is old! Used one of these for a while long ago.
http://camerapedia.wikia.com/wiki/Canon_Pellix
http://camerapedia.wikia.com/wiki/Canon_Pellix
Sony uses the pellicle mirror in some of their newer cameras too. Canon may have started it in the 1960's but it is still being used today. Odd?
https://en.wikipedia.org/wiki/Sony_SLT_camera
Nov 8, 2015 13:49:39 #
srron wrote:
This has probably been thought of already, but I wonder if it would be feasible to place the mirror on the front of the shutter curtain thereby eliminating the swing away mirror.
Err... It already is. Why else is the mirror lifted BEFORE the curtains comes down on this idea?
There was a technology that was starting to develop in the 'old time' where the mirror was static. That slowed down the camera quite a bit (2 stops?). That went off the radar when digital came along because digital already way too slow at the time (early 2000).
Now the ISO is incredible but offer so many disadvantages (two types of noise, lower dynamic range) that returning to this technology is still not viable. Time will tell. Seeing that many manufacturers are moving toward digital display vs optical I do not see it coming back thought.
Nov 8, 2015 13:53:22 #
If we even want to [I]keep[/] the mirror, it could also become the shutter if it could go from opaque to transparent when a brief current is applied. No moving mirror, no moving shutter. That would simplify flash sync issues as well. No more traveling slits! Lots to overcome: other technical issues aside, degradation of the image from passing through the mirror/shutter is the first thing that pops into my head. Seems like I read something somewhere on that.
After playing with an Olympus OM-D E5 MkII for the last few weeks, I can see how FDSLR* mirrorless cameras are gaining in popularity. Impressive little camera.
FDSLR* =Faux Digital Single Lens Reflex
After playing with an Olympus OM-D E5 MkII for the last few weeks, I can see how FDSLR* mirrorless cameras are gaining in popularity. Impressive little camera.
FDSLR* =Faux Digital Single Lens Reflex
Nov 9, 2015 16:32:56 #
Mac wrote:
Wouldn't that add weight to the shutter curtain thus slow down shutter speed?
It's not the weight, it's the inertia induced by the additional mass that would cause issues.
F=ma
F=Force
m=mass
a = acceleration.
The more mass you have to move out of the way to get the shutter-mirror assembly to operate, the more Force you have to apply to that much more mass.
Then the opposite occurs once one gets that mass moving.
p = mv
p=momentum
m=inertial mass
v=velocity
Once you get that mirror-shutter moving it's going to want to continue to move (Newton's Laws)
The inertia of that moving mirror is going to have to be overcome by some decelerating force. Then it would have to be accelerated in the opposite direction to reset the shutter.
Slapping that much more mass around is going to have a negative affect on holding the camera still. The vibrations induced by all of that would be difficult to manage.
--Bob
Nov 9, 2015 16:42:44 #
Leitz
Loc: Solms
rmalarz wrote:
It's not the weight, it's the inertia induced by t... (show quote)
So you can have mass without weight?
Nov 9, 2015 17:02:52 #
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