Alley in Pisa, Italy

by Lars Kotthoff

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20

ISO is very useful as it helps overcome read noise by amplifying a weak analogue signal prior to digitization (which adds a more or less constant amount of noise) thus giving a better signal to noise ratio. That's all raising the ISO does, amplify the signal. It does not make the picture noisier because it only amplifies what's already there. See this ...


19

Body - you can get better high ISO performance from a full frame body, if you're willing to rent one. That's worth a couple of stops. Lens - another couple of stops if you buy/hire an f/1.4 or f/1.8 lens, especially if you're shooting at the long end of your zoom at f/5.6 Light - in the picture you've given as an example, you seem to be standing in the ...


13

If the result you are looking for is a photograph, the short answer is no. The same equipment won't give better results with video than it can with stills. I think the apparent difference is due to exactly one thing: resolution. Try taking one of your still frames, resampling down so it's 1080 pixels tall, and then comparing. There isn't any inherent ...


10

Assuming all other exposure settings with and without flash are equal, then using flash means you are adding light to the scene. Increased light in the scene means increased light down the lens, which means more light at the sensor. That means you have a higher signal to noise ratio at the sensor, which generally means less noise. Signal to Noise ratio, or ...


10

Yes, it is useful as there are some situations where there just isn't enough light to take photos at low ISOs. I take quite a few photos of the am-dram productions I'm involved in, and even with a F1.8 lens I often find myself shooting at an ISO between about 800 and 1600 in order to be able to have a short enough shutter speed to freeze the action. It's ...


9

Your idea is on the right basic track — you could meter at the limit of your camera, and then change to what the camera thinks is underexposure. ISO 3200 is actually only one stop faster than 1600 (each doubling is one stop). You say "points", and it may be that your lens has click points at half stop, in which case yes, two clicks would be right. (If you're ...


9

Shooting action in low-light conditions or freezing very fast action are common situations where you might need to compromise on the ISO to get the shot. For example, I recently shot some pictures of jets passing by at an air show. I found that even at noon on a day with clear skies and the aperture at 2.8, ISO 100 was too low to get me the shutter times I ...


9

There has been an improvement between the 40D and 650D, but not that great. Certainly less than a stop. You'll get a far far greater improvement in image quality by getting more light onto the sensor. There are a number of ways to achieve this: Depending on what lens you're currently using you may be able to get a three stop improvement by switching to a ...


8

I believe it may be a flaw in your testing. Raising ISO should not be getting you a higher signal to noise ratio (or usable dynamic range). You are raising the noise floor, without any corresponding increase in dynamic range at the bright end. Thus you should be left with overall lower dynamic range. It would not be possible to go the other way. Is it ...


7

The cheap option: create monochrome images. (some may even look great in monochrome) The image you have shown there is mostly lit by tungsten light. This light contains very little blue light, and therefore the blue channel in the image will have a very poor signal to noise ratio. When you perform white balance correction, the blue channel will be amplified ...


6

Sure, high ISO is relevant. I'm a journalist and very often I have to take pictures in conditions where I can't use flash, but to have a picture is much more relevant than the quality of the picture. Moreover, if you take a picture for a regular newspaper there is no difference if one uses ISO 200 or 1200 - printing will be worse either way...


6

You misunderstand how exposure compensation works. Exposure compensation is not an actual physical thing the camera uses to control light - there are only 3 real things that control the amount of light: Aperture, Shutter speed and ISO. Exposure compensation is a way to tell the camera in one of the auto/semi-auto modes you want to override the light meter ...


5

With the parents permission, you are going to get the best results by putting a remotely triggered flash unit on her balcony. Then you expose for the ambient and adjust flash power to light her properly -- at dusk this could be a really cool shot. This is much cheaper than a 300mm f/2.8 and will greatly expand your capabilities as a photographer. Pick up a ...


5

High ISO performance has greatly improved over the last few years but if you scrape the bottom of the barrel you wont see much improvement! While test results for the T4i are not out yet, if you compare the T3i to the 40D at DXO lab, their scores is almost identical (54 vs 64) and looking at the low-light scores in particular, you will see 793 vs 703, ...


5

This problem is caused by electromagnetic interference generated by the SWM in many Nikon lenses, and possibly by the camera's own electronics as well. There are cases where Canon lenses with USMs have caused banding. See this dpreview forum thread for an instance of sensor banding caused by a USM lens mounted on a Canon DSLR.


5

I can see two possibilities that aren't related to post-processing either in or out of camera. First, increase the light, either through changing the scene or by using wider aperture and longer shutter — and thereby lowering the required ISO. This doesn't seem exactly in the spirit of your question, though. So, second: let the darker scenes be themselves. ...


5

High ISO can be a factor (see Is there a technique to increase saturation in high ISO?), but I suspect that another effect you are seeing is the decrease of natural-full spectrum light relative to the fluorescent light source — see How does light quality vary between fluorescent (CFL) and incandescent? (with sunlight being roughly the same as incandescent in ...


5

Exposure compensation is just another means of changing either shutter or aperture. I is not some fourth component of exposure, there are still only three: ISO, Shutter Speed, Aperture. If you have manually selected an aperture, changing EC will reduce shutter speed. If you have manually selected a shutter speed, changing EV will increase the size of the ...


4

Use a faster lens (f/2.0 for example) Use a monopod, these are more portable and still provide some more steadiness Hold your camera against a wall, put it on a fence or other steady object (serving like a tripod). Be aware of scratches to the body.


4

I have a D4 and can see very very slight banding from 10000/12800, and if under exposed can be seen at 25600 especially at 51200. If over exposed banding is visible slightly on 25600. If post process +1 exposure then banding is visible above 8000/10000 iso. Tested with AF on and OFF and makes no difference, is very random and is mostly seen in the darker ...


3

How about a big old it depends. If video is what you want/can use then yes. Because while the video has a ton of blurring and focus issues (which you would have also had shooting stills), it also has a single large advantage -- a massively powerful image analyzer -- your brain. You brain will merge frames, follow motion, and forgive much more than it will ...


3

Darktable has a great profile-based noise removal tool. You may give it a try if your sensor is already supported. If not, you can submit an own profile. See http://www.darktable.org/2012/12/profiling-sensor-and-photon-noise/ for all the glory details. It is especially smoothing with the option "wavelets".


3

Just found out this line of products from Ilford. The description is the following: The ILFORD XP2 Super Single Use Camera gives the convenience of being able to have the film processed at any High Street photo-processing centre using C41 colour negative systems, with proof prints made on colour paper. These can either be close-to-neutral black and white ...


3

This isn't specifically a Canon example (it's the Pentax K-5), but here's a shot I took at ISO 20000 (converted from DNG): You can see a larger version here. Of course, I did noise reduction and you can easily see detail loss, but it's a very usable shot. Heck, I did use it as part of my Project 365 back in 2010. So, the technology of the sensors have ...


3

I'd say it's extremely useful, because photography is about capturing good looking light, and it's easier for light to look good when there's not much of it, e.g. at night, at sunset/dawn, in pubs, at concerts, in the woods. That's why the industry strives to make sensors (and film, in the past) with good high iso performance and fast lenses, and ...


3

To answer the second question you ask, ISO really does affect the performance and one thing to keep in mind is that the higher the ISO you use the more noise you will end up with in your image. Although, this is being improved upon and becomes less of an issue with each successive generation of cameras.


3

You are correct that there is no free lunch. Software NR works by looking for sharp edges and trying to identify what is detail and what is noise, but at a very fine level, they can't be distinguished. What you will normally see with light NR is a reduction in fine detail, but gross detail is maintained. The more you turn up NR, the more gross the detail ...


3

You're correct, a higher ISO will introduce noise and cause detail to be lost. However, it's important to understand how far you can increase ISO before it makes a noticeable impact. By the numbers, I'm sure that increasing one stop from 100 to 200 will undoubtedly result in a nearly imperceptible difference under pretty much any condition. I bet going from ...


3

Masking the foreground and denoising the background is a good technique when the background is out of focus. You would get a slightly better result using a dedicated noise removal plugin (noiseninja or neatimage, or one of the inbuilt Photoshop tools). Gaussian blur is a bit of a blunt instrument, whilst it's good at removing pure random noise it is not as ...



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