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Analog Lens F stop low light for digital
If you put a 400mm analog lens on a digital SLR camera, you will have
around a 600mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. Using the 400mm on our analog Canon in Africa, has been working pretty well. The results have been ok for our armature photography skills and taste. . But, I was wondering that with the 1.5x conversion and the low F stops, shooting with 400m converted to 600m would make shooting with this lens hard to do, like very obviously too low a light conditions at sunset or early sunrise. Daytime should be ok? Thanks, Jon |
#2
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It has no impact. It's just like shooting film & cropping the edges off
then printing larger. That's the only difference. In fact for a 6MP camera, you probably could get the same print with a cropped 35mm film print. scubatv wrote: If you put a 400mm analog lens on a digital SLR camera, you will have around a 600mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. Using the 400mm on our analog Canon in Africa, has been working pretty well. The results have been ok for our armature photography skills and taste. . But, I was wondering that with the 1.5x conversion and the low F stops, shooting with 400m converted to 600m would make shooting with this lens hard to do, like very obviously too low a light conditions at sunset or early sunrise. Daytime should be ok? Thanks, Jon |
#3
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scubatv wrote:
If you put a 400mm analog lens on a digital SLR camera, you will have around a 600mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. Using the 400mm on our analog Canon in Africa, has been working pretty well. The results have been ok for our armature photography skills and taste. . But, I was wondering that with the 1.5x conversion and the low F stops, shooting with 400m converted to 600m would make shooting with this lens hard to do, like very obviously too low a light conditions at sunset or early sunrise. Daytime should be ok? Thanks, Jon The 400mm lens remains a 400mm lens, so the same light/aperture/shutter speed parameters remain. However, the 400mm lens on the digital body has the same *angle of view* as a 600mm lens would have on a film body (and the 1/focal-length rule of thumb becomes the 1/(focal-length * 1.5) rule of thumb.) -Dave |
#4
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If you put a 400mm analog lens on a digital SLR camera, you will have
around a 600mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. The F values are the ratio of lens length to aperture size. The amount of light transmitted by the lens is directly related to this ratio and it doesn't change just because the back focus is longer or shorter to accommodate different size film/sensors. -- Mark Lauter Photos, Ideas & Opinions http://www.marklauter.com |
#5
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"scubatv" wrote in message ups.com... If you put a 400mm analog lens on a digital SLR camera, you will have around a 600mm lens. No, your lens now shows an image which has the angle of view of a 600 mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. No more restricted than it is on a film camera, except you don't see as much of the scene. By the way, the reduced image size has the advantage of using the sharper part of the circle of illumination of the lens. It might result in a sharper image on the digital camera. Using the 400mm on our analog Canon in Africa, has been working pretty well. The results have been ok for our armature photography skills and taste. . But, I was wondering that with the 1.5x conversion and the low F stops, shooting with 400m converted to 600m would make shooting with this lens hard to do, like very obviously too low a light conditions at sunset or early sunrise. No the changed angle of view has no influence on the exposure. Daytime should be ok? As good as it is on the film camera. Jim Thanks, Jon |
#6
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"Mark Lauter" wrote in message .. . If you put a 400mm analog lens on a digital SLR camera, you will have around a 600mm lens. Our 400mm lens is F 4.5-.6.7 which is pretty low light. Could anyone comment on just how restricted the lens would be shooting at 600mm. The F values are the ratio of lens length to aperture size. The amount of light transmitted by the lens is directly related to this ratio and it doesn't change just because the back focus is longer or shorter to accommodate different size film/sensors. -- Mark Lauter Photos, Ideas & Opinions http://www.marklauter.com The "Back Focus" has not changed. The only thing that has changed is that the Sensor is smaller than a 35mm Film Frame. It is placed the same distance from the Lens Flange as a Film would be. The smaller sensor only "Sees" the central portion of the Image projected by the lens. If this distance was not maintained Infinity Focus would be out. Roy G |
#7
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In message . com,
"scubatv" wrote: If you put a 400mm analog lens on a digital SLR camera, you will have around a 600mm lens. The more correct way of saying this is that it has a field of view equivalent to 600mm on a 35mm camera. It is still, and always will be, a 400mm lens. If you start calling it 600mm, someone is going to come along, and multiply it again to 900mm. Our 400mm lens is F 4.5-.6.7 which is pretty low light. That's pretty dark for deep woods, and dusk and dawn, but the high ISOs on the Canon DSLRs work pretty well. Get out there and try; you're the only one who can judge if it's worth doing; you set the quality standard. What I do when light is getting low, is to set the camera to the slowest shutter speed in Tv mode that will freeze the action and the shaking, RAW, and ISO 1600 with +1 EC. That represents an exposure index of (ISO) 800, and if there is enough light, I get a nice "800" exposure with hardly any noise. If the light is too low, the camera will fail to achieve +1 EC, and I will have an ISO 1600 shot, or even a higher exposure index, which will have to be pushed in the RAW converter. Sometimes even images that are still dark, even with the maximum push in the RAW converter, can look usable if you push them further in the image editor with the Levels tool, but they will look best if you convert to an image mode like Lab or HSV, and blur everything but the luminance channel, and then, if necessary, downsample the image for noise-less display. Could anyone comment on just how restricted the lens would be shooting at 600mm. Using the 400mm on our analog Canon in Africa, has been working pretty well. The results have been ok for our armature photography skills and taste. . If it works fine for film, then you should be OK with the digital. Canon DSLRs outperform 35mm film at high ISOs. But, I was wondering that with the 1.5x conversion and the low F stops, shooting with 400m converted to 600m would make shooting with this lens hard to do, like very obviously too low a light conditions at sunset or early sunrise. Daytime should be ok? Exposure and lighting issues should be the same as the film; the digital sensor you have is merely smaller than a 35mm frame, and works like a crop of one. You will, however, have a shorter maximum shutter time, assuming that the output will be viewed at the same size as the full 35mm-frame image, since any blur do to camera motion will be 1.5x as large or long. -- John P Sheehy |
#8
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Ok, I might have made a boo boo here.
After talking to Canon, the tech said, for wildlife photography, if you are not interested in speed, any card will do. Any card. So, at egghead.com, I bought 2 Kingston 1gb CF/1024. Their lowest quality/rated card for $113. not including a $30 rebate. .. If I'm reading the charts right, it will take 2 seconds to write a raw file to this card. That will certainly create a data bottle neck, correct? How long will I have to wait to take pictures between shots? Sorry, for being so lame, I'm on the video side of photography and these numbers don't seem to penetrate well. Thanks, Jon |
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