Shutter Speed Quandry
Jan 2, 2016 22:17:04 #
I recall the "rule" of using the reciprocal of the length of a lens as its minimum shutter speed ( 100 mm = 1/100). What I am having a difficult time understanding is WHY this would change from crop sensor to full frame.
I guess my difficulty in understanding this is what would be the relationship since the length of the lens has not changed. Light would not act any differently on the lens in either case. The difference would be how the sensor interprets the light, not how the lens impacted it.
A good exposure and focus would be the same with the lens on either sensor.
Perhaps, I am missing something or just plain misunderstanding some relationship. I hope some of our learned members can help clear this up.
I guess my difficulty in understanding this is what would be the relationship since the length of the lens has not changed. Light would not act any differently on the lens in either case. The difference would be how the sensor interprets the light, not how the lens impacted it.
A good exposure and focus would be the same with the lens on either sensor.
Perhaps, I am missing something or just plain misunderstanding some relationship. I hope some of our learned members can help clear this up.
Jan 2, 2016 22:22:37 #
I think it's more about the perceived magnification of the focal length, and the real magnification of camera movement in enlargement.
Jan 2, 2016 22:25:44 #
the smaller sensor is less tolerant of motion.
The speed should be 1 over twice the mm in length.
The speed should be 1 over twice the mm in length.
Jan 2, 2016 22:40:13 #
larrywilk wrote:
I recall the "rule" of using the recipro... (show quote)
It doesn't. Focal length of a lens is the same regardless of format. Angle of view is what changes. Focal length is determined by the distance from the nodal point of a lens to the film plane. It has nothing to do with format.
Jan 2, 2016 22:48:10 #
Darkroom317 wrote:
It doesn't. Focal length of a lens is the same regardless of format. Angle of view is what changes
You MUST apply the crop factor.
That rule of thumb was for 35mm cameras.
With a camera that has,say a 4x crop factor, 100mm equivalent lens would be 25mm. VR aside, 1/25th of a second would give you a lot of camera movement.
Jan 2, 2016 22:51:59 #
GoofyNewfie wrote:
You MUST apply the crop factor.
That rule of thumb was for 35mm cameras.
With a camera that has,say a 4x crop factor, 100mm equivalent lens would be 25mm. VR aside, 1/25th of a second would give you a lot of camera movement.
That rule of thumb was for 35mm cameras.
With a camera that has,say a 4x crop factor, 100mm equivalent lens would be 25mm. VR aside, 1/25th of a second would give you a lot of camera movement.
100mm is 100mm. So you would shoot is at 1/100 of a second, regardless of format. I don't know why one would shoot a 100mm at 1/25. Does any manufacturer describe a 100mm lens as 25mm?
Jan 2, 2016 22:57:48 #
Before image stabilization it was a rule of thumb to prevent blurring your pictures when hand holding the camera. That's all, nothing else
larrywilk wrote:
I recall the "rule" of using the recipro... (show quote)
Jan 2, 2016 22:59:15 #
Darkroom317 wrote:
It doesn't. Focal length of a lens is the same regardless of format. Angle of view is what changes. Focal length is determined by the distance from the nodal point of a lens to the film plane. It has nothing to do with format.
This rule of thumb for shutter speed being equal to 1/focal_length is actually 1/effective_focal_length.
Hence if we have a 100mm lens and use it on a full frame camera the rule of thumb is to use a shutter speed of 1/100 second. On a 1.5X crop APS-C sensor the rule of thumb would suggest a 1/150 second shutter speed.
Jan 2, 2016 23:03:09 #
Darkroom317 wrote:
100mm is 100mm. So you would shoot is at 1/100 of a second, regardless of format. I don't know why one would shoot a 100mm at 1/25
Neither do I.
I read the question as addressing camera movement.
If some moron directly applied the 1/ focal length guide, he might think he could possibly hand hold a 4x crop factor camera with a 100mm equivalent lens steady at 1/25th because that's the focal length he would have. You have to use the crop factor.
Granted, a DX and FX camera aren't enough of a difference to really matter but it is a consideration.
Jan 2, 2016 23:04:02 #
Having steady hands count also.
larrywilk wrote:
I recall the "rule" of using the recipro... (show quote)
Jan 2, 2016 23:04:10 #
Apaflo wrote:
This rule of thumb for shutter speed being equal to 1/focal_length is actually 1/effective_focal_length.
Hence if we have a 100mm lens and use it on a full frame camera the rule of thumb is to use a shutter speed of 1/100 second. On a 1.5X crop APS-C sensor the rule of thumb would suggest a 1/150 second shutter speed.
Hence if we have a 100mm lens and use it on a full frame camera the rule of thumb is to use a shutter speed of 1/100 second. On a 1.5X crop APS-C sensor the rule of thumb would suggest a 1/150 second shutter speed.
Hmm. Interesting, never seen it described as equivalent focal length. Would that be all based around 35mm? So, given that a 50mm lens on a 6x7 camera is the equivalent of around 23mm on 35mm, could I get away with 1/25 with a 6x7 camera? What about 1/25 with a 4x5 press camera and a 90mm lens?
Jan 2, 2016 23:08:06 #
Darkroom317 wrote:
Hmm. Interesting, never seen it described as equivalent focal length. Would that be all based around 35mm? So, given that a 50mm lens on a 6x7 camera is the equivalent of around 23mm on 35mm, could I get away with 1/25 with a 6x7 camera?
Yep.
Think of how much you have to enlarge each image to the same size, say 8x10.
A large neg, say 4x5 needs very little enlargement, that 4x crop factor camera (if one exists) needs a whole lot of enlargement which reveals lots of faults, including camera movement. (Noise or grain issues aside)
Your mileage may vary..
Jan 2, 2016 23:11:50 #
GoofyNewfie wrote:
Yep.
Think of how much you have to enlarge each image to the same size, say 8x10.
A large neg, say 4x5 needs very little enlargement, that 4x crop factor camera (if one exists) needs a whole lot of enlargement which reveals lots of faults, including camera movement. (Noise or grain issues aside)
Think of how much you have to enlarge each image to the same size, say 8x10.
A large neg, say 4x5 needs very little enlargement, that 4x crop factor camera (if one exists) needs a whole lot of enlargement which reveals lots of faults, including camera movement. (Noise or grain issues aside)
Interesting. Sorry I don't ever think about crop factors, as the base format is relative. It is terminology that I am with which I am not familiar. So, the notion of 4x crop camera is confusing. I suppose this would be like a digital P&S.
Jan 2, 2016 23:14:28 #
Darkroom317 wrote:
Hmm. Interesting, never seen it described as equivalent focal length. Would that be all based around 35mm? So, given that a 50mm lens on a 6x7 camera is the equivalent of around 23mm on 35mm, could I get away with 1/25 with a 6x7 camera? What about 1/25 with a 4x5 press camera and a 90mm lens?
That's it!
The connection is the amount of movement any given amount of camera shake will generate on the image. With a larger sensor it takes more angular movement to cause any given fixed amount of blur. The focal length is just a handy representation of how much that is magnified.
Yes, it is all based on 35mm film. Since the 1950's most "advanced" photographers have been using 35mm cameras to learn how everything relates. Before that the "normal" thing was almost anything. And now that electronic sensors have become popular we are back to a variety of common sizes. But all of us old farts do understand how it relates to 35mm... and some can't relate to anything else!
Jan 2, 2016 23:16:41 #
Darkroom317 wrote:
Interesting. Sorry I don't ever think about crop factors, as the base format is relative. It is terminology that I am with which I am not familiar. So, the notion of 4x crop camera is confusing. I suppose this would be like a digital P&S.
Most likely- math is not my thing.
I honestly think with heavier cameras, like the RB, you could go lower.
With the L bracket and a good grip position, I felt I could hold it steadier than my 35mm stuff. (At least initially, before I got fatigued)
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