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Canon 50D Auto ISO Question
Anyone know if the Canon 50D has programmable auto ISO like the Nikon
system? For example, you can program the lowest shutter speed you want to use and it will automatically increase the ISO if it needs a slower shutter speed than that for correct exposure? For example, if you are shooting at ISO 100 in AV and pre set the lowest shutter speed to 1/30, if it needs 1/15 it will automatically bump it up to ISO 200 and use 1/30 instead? Also, can you set the maximum ISO it will automatically choose? For example, if you don't want it to automatically go above ISO 800, you can set it to stop at this ISO? |
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Canon 50D Auto ISO Question
wrote in message
news Anyone know if the Canon 50D has programmable auto ISO like the Nikon system? It would appear to have some type of auto-sio function which is no where as customizable as Nikons. For example, you can program the lowest shutter speed you want to use and it will automatically increase the ISO if it needs a slower shutter speed than that for correct exposure? For example, if you are shooting at ISO 100 in AV and pre set the lowest shutter speed to 1/30, if it needs 1/15 it will automatically bump it up to ISO 200 and use 1/30 instead? Doesn't appear so. It would appear you have to use Tv mode to set a shutter speed. In manual mode it appears setting this results in fixed iso400. Also, can you set the maximum ISO it will automatically choose? For example, if you don't want it to automatically go above ISO 800, you can set it to stop at this ISO? Doesn't appear to be the case. DL a copy of the manual and look at p64 yourself. Cheers. Just looked at the manual, but doesn't seem to give much info on how it works. Unfortunately, I don't know anyone with a 50D that I can play with either. If you can't tell it what minimum shutter speed you want, I wonder what parameters it uses? For example, does it just use a base shutter speed setting of say 1/60? Does it change depending on what focal length is being used, and if so, does it takes IS into consideration? |
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Canon 50D Auto ISO Question
"Paul" wrote in message ... Anyone know if the Canon 50D has programmable auto ISO like the Nikon system? For example, you can program the lowest shutter speed you want to use and it will automatically increase the ISO if it needs a slower shutter speed than that for correct exposure? For example, if you are shooting at ISO 100 in AV and pre set the lowest shutter speed to 1/30, if it needs 1/15 it will automatically bump it up to ISO 200 and use 1/30 instead? Also, can you set the maximum ISO it will automatically choose? For example, if you don't want it to automatically go above ISO 800, you can set it to stop at this ISO? It is an obvious extension of shutter priority. You select the speed and it automatically selects the aperture, and once the lens is wide open starts increasing the ISO until you need flash. You could also auto adjust - the camera will pick a suitable aperture and speed, but once the speed it too slow for hand held it starts adjusting the ISO, unless it detects a tripod. |
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Canon 50D Auto ISO Question
wrote in message
... On Thu, 9 Oct 2008 14:35:29 +0100, in rec.photo.digital.slr-systems Cheers. Just looked at the manual, but doesn't seem to give much info on how it works. Unfortunately, I don't know anyone with a 50D that I can play with either. If you can't tell it what minimum shutter speed you want, I wonder what parameters it uses? For example, does it just use a base shutter speed setting of say 1/60? Does it change depending on what focal length is being used, and if so, does it takes IS into consideration? Can't help you here, I shoot Nikon's, was just interested enough to look given I have a few friends and know their 20Ds don't have any kind of auto-iso function. I use it a fair bit, though really wish Nikon would allow faster minimum shutter speeds to be set than the 1/250s in my D200/D300. No probs. I think I have found the answer. Looking at a review of the 5D II, it says the following: "Auto ISO in all modes except manual: The Mark II now features an automatic ISO option where the camera selects the sensitivity (in the range ISO 100 - 3200). In Auto, Program and Aperture Priority the camera attempts to maintain a minimum shutter speed of 1/focal length (hence with a 24 mm lens it will try to maintain 1/25 sec or faster). In manual mode Auto ISO is fixed at ISO 400." I would assume that the 50D is the same (apart from ISO 1600 Max). Although there is no mention if this changes if you are using a lens with IS. Not a problem if ISO 1600 on a 50D is totally noise free. As it isn't, I would prefer it to give you the option to manually over-ride it. It sounds like at 300mm it will select 1/320, when I know I can get away with 1/30 on a lens with IS if the subjects are relatively still and so could use a much lower ISO. The Nikon system seems to allow you to tell the camera what you want, but doesn't take focal length into concideration. The Canon system takes focal length into concideration, but AFAIK doesn't allow you to over-ride the camera. |
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Canon 50D Auto ISO Question
Why not have a true ISO priority mode?
You choose the shutter speed and you choose the aperature, and the ISO is adjusted automaticlaly. Is any DSLR manufacturer doing this? |
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Canon 50D Auto ISO Question
In article , just bob
wrote: Why not have a true ISO priority mode? You choose the shutter speed and you choose the aperature, and the ISO is adjusted automaticlaly. Is any DSLR manufacturer doing this? just use auto iso in manual mode. |
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Canon 50D Auto ISO Question
just bob wrote:
Why not have a true ISO priority mode? You choose the shutter speed and you choose the aperature, and the ISO is adjusted automaticlaly. No, true ISO priority would be you chose the ISO, and the shutter speed and aperture are adjusted automatically - like P mode on most cameras. Is any DSLR manufacturer doing this? What you describe (you set shutter speed & aperture, ISO adjusted automatically) sounds very like the TAv mode on the Pentax K20D. Pentax also seem to have a few other clever settings, such as program line adjust and their "Green" mode, which look like they could do all the OP was asking for and more. -- Alex Monro Exeter, UK Running on Linux (Kubuntu 7.1) |
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Canon 50D Auto ISO Question
In rec.photo.digital Paul wrote:
| I would assume that the 50D is the same (apart from ISO 1600 Max). Although | there is no mention if | this changes if you are using a lens with IS. | | Not a problem if ISO 1600 on a 50D is totally noise free. As it isn't, I | would prefer it to give you the option to manually over-ride it. It sounds | like at 300mm it will select | 1/320, when I know I can get away with 1/30 on a lens with IS if the | subjects are relatively still and so could use a much lower ISO. I have a 450D. It allows me to choose an ISO in M, Av, and Tv modes. I have a choice of 100, 200, 400, 800, 1600, and "AUTO". I'm guessing at what actually happens with an ISO setting. I believe it uses this setting to determine how to interpret the raw pixels values captured by the sensor to convert the image into a JPEG file. This would emulating using different film speeds (which are intrepreters of incident light levels). If my guess is correct, then the RAW files should be the same under the same exposure setting, regardless of the ISO setting. Presumably the "AUTO" setting for ISO would choose an ISO interpretation that produces a better light balance for the given exposure conditions. | The Nikon system seems to allow you to tell the camera what you want, but | doesn't take focal length into concideration. The Canon system takes focal | length into concideration, but AFAIK doesn't allow you to over-ride the | camera. I have manual settings on my 450D that let me control the exposure, and so far it has let me do whatever I want, even if it is dumb (like bracketing across 20 stops). A higher ISO is going to take a weaker exposure and crank it up numerically to have values that in a JPEG file will display at visible pixel values. If the exposure really is weak, there will be more noise. That's just a fact of science. You can post process the files (either RAW or JPEG, but you get all the original info with RA) to crank up the effective ISO even beyond the maximum 1600 setting, but you will get even more noise that way. You could reduce noise by chilling the sensor. Special cameras for astrophotography do that. Some have simply heat sinks. Others have active cooling systems. A radical one might even have liquid nitrogen cooling (I've heard of it being done). -- |WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance | | by the abuse department, bellsouth.net is blocked. If you post to | | Usenet from these places, find another Usenet provider ASAP. | | Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) | |
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Canon 50D Auto ISO Question
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Canon 50D Auto ISO Question
"Paul" wrote in :
Anyone know if the Canon 50D has programmable auto ISO like the Nikon system? No. It has an "auto" value for ISO, but it is programmed by morons, who don't seem to understand anything about how Canon DSLRs work in regards to ISO and noise, or about the needs of users. For example, you can program the lowest shutter speed you want to use and it will automatically increase the ISO if it needs a slower shutter speed than that for correct exposure? For example, if you are shooting at ISO 100 in AV and pre set the lowest shutter speed to 1/30, if it needs 1/15 it will automatically bump it up to ISO 200 and use 1/30 instead? No. 50D auto-ISO gravitates to ISO 400 Also, can you set the maximum ISO it will automatically choose? For example, if you don't want it to automatically go above ISO 800, you can set it to stop at this ISO? No, but it doesn't go above 400 unless it really, really needs to. Even if you have it set to Tv-priority, it will hold the ISO down to 400 when it should be at 1600, which makes absolutely no sense, as ISO 400 will give a noisier image than 1600 when 1600 is the right ISO for the maximum aperture, the set shutter speed, and the lighting. In manual exposure mode, "auto-ISO" is fixed at ISO 400! Manual exposure (TAv) mode is the one where I would use a properly-working auto-ISO the most. An intelligent auto ISO should have *NO* hesitation to raise the ISO as necessary, at least in manual exposure mode ("TAv") and in Tv mode. There is no intelligence, whatsoever, in Canon's system. Whoever is making the decisions on auto-ISO for Canon is an incompetent moron. I really don't understand why so many people are interested in limiting the high end of ISO. My problem with Canon "auto-ISO" is that it doesn't go high enough. Do you like blurred images? Under-exposed images? |
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