I have canon 80d and lens EF-S 17-55mm f/2.8 IS USM, when I need to reduce the F to F22, the light will be very low or dim especially in the video mode, So in this case, I must increase the iso to about 12000 , but the last value would produce the video five with very noise. so with my lens, I can not definitely use the value of F22 which is very useful in some case to reduce or get rid of Blur for the background of things, so please recommend me?
-
Welcome to the new forums! Please read this first. For known issues we are working to resolve, click here.
problem with Fnumder and iso
- Thread starter srmdnadem
- Start date
-
- Tags
- canon eos 80d
Steve Balcombe
Forum Pro
You can't have everything. If you absolutely must use f/22, then you will have to add more light. If you can't add more light, you will have to accept the noise. If you can't accept the noise, you will have to use a larger aperture...
M
Mark B.
Guest
What and why are you shooting at f/22? This will lead to soft images due to diffraction.
rmexpress22
Senior Member
- Messages
- 2,410
- Solutions
- 7
- Reaction score
- 1,563
If you need more DoF, use a wider angle and back up a little bit. At 17mm wide open you'll have a good amount of DoF as long as you back up from the subject a bit.
Dan Marchant
Senior Member
Photography requires light. If you do something that reduces the light reaching the sensor (such as using a small aperture F/22) you have to counter balance that by doing something to increase light. That means a slower shutter speed, higher ISO or adding more light by using artificial lights.
John Sheehy
Forum Pro
Welcome to the reality of finite light.
For video, use the minimum exposure time allowed, and ISO 12800 shouldn't be all that bad, if you need f/22.
Careful, though; good video settings can be horrible for stills, and visa-versa, and it is easy to ruin images switching back and forth without changing all the settings. It is really stupid that cameras don't sport separate settings for stills and movies initiated with different buttons. I never want to use the same settings, so why are they the same unless I change them - ridiculous.
rdspear
Senior Member
More light
ThrillaMozilla
Veteran Member
I suggest that you try it first with all automatic settings. The camera does an amazing job of making appropriate choices. Although those choices may not be ideal for all situations, you may be pleasantly surprised. I especially recommend this because it sounds like you are not all that familiar with the camera settings.
rdspear
Senior Member
What focal length are you trying to use, how far away is your subject, and how far is the background that you're trying to keep in focus.
There are simple laws of physics that are just realities in some situations.
There are simple laws of physics that are just realities in some situations.
davel33
Senior Member
ThrillaMozilla
Veteran Member
No, don't get it. I checked the reviews, and that book makes use of the so-called exposure triangle--which is nonsense. The concept will mislead you and rot your brain.
Photographic exposure is the amount of light (per unit area) striking the sensor. It was that way in the era of film, and it's still that way. This has been discussed very thoroughly in the Photographic Science and Technology DPR forum, If anyone wishes to dispute this, please take the dispute there, and they will set you straight.
Last edited:
davel33
Senior Member
With statements like " rot your brain" I have to wonder if you have have the ability to comprehend the exp triangle.
rdspear
Senior Member
And all this talk of shutter speed and aperture have no impact on that. No relationship among them whatsoever....
And Windows is for brain rotted idiots - you should use text-based Linux - everyone knows it's better...
ThrillaMozilla
Veteran Member
Well, talk has no impact on it, but the camera settings do. If you want an extended, more precise statement of what exposure is (and I hope you do), Wikipedia has a concise, correct definition (emphasis added):
"In photography, exposure is the amount of light per unit area (the image plane illuminance times the exposure time) reaching a photographic film or electronic image sensor, as determined by shutter speed, lens aperture and scene luminance. Exposure is measured in lux seconds, and can be computed from exposure value (EV) and scene luminance in a specified region."
In the Talk section there is also a discussion and a link on why the ISO setting is omitted from the article:
"The Exposure Triangle was re-inserted 31st August 2017, along with a caption incorrectly suggesting that ISO is a component of exposure. The error was pointed out in a discussion on DPReview (https://www.dpreview.com/forums/post/60075158) I agree with the two contributions above. References to the badly conceived 'Exposure Triangle' are unhelpful for people trying to understand exposure."
Photography is inherently technical at its base. Anyone who wants to optimize image quality will need to understand the relation between exposure parameters, depth of field and noise. Using standard terminology is necessary for that understanding.
The essential concept (which is unfortunately omitted from the article) is that less exposure creates a noisier image. In digital photography the effect of the ISO setting is confusing because it conflates analog gain, digital gain, and image tags in a camera-specific and unspecified way. The effect of the ISO setting varies considerably from camera to camera. That subject is considered separately from exposure.
If you want to ask questions, please take it to the other forum. There you will find experts on the subject, many of whom have invented the technology that we use. I'm not going to reply further in this thread.
Last edited:
Keyboard shortcuts
- f
- Forum