I used to believe that ISO adds noise as a drawback to increasing exposure, but after researching the topic I arrived at the conclusion that it is a misconception. By amplifying the existing signal from the electron well (please correct my terminology if it's wrong), any noise that might be apparent in the final photo will exist there no matter what ISO setting might be chosen. The reason the noise is apparent at high ISOs, is that underexposed areas, which have a lower signal-to-noise ratio, get amplified. Whether this effect is achieved through ISO or through post-processing software should be irrelevant, and the end result should be the same. Meanwhile, the benefit of raising the ISO in this situation should be the greater variance in half-tones.  So I did some tests, and invariably there is actually more noise in same photos taken at 100 ISO and given +5 EV in post, vs same photo taken at 3200 ISO. Here is an example:   According to my understanding, the noise levels should be virtually the same. What is causing noise at 100 ISO? My only guesses are:   Higher read noise at lower brightness Something to do with logarithmic exposure and the way the image is stored The camera actually captures more photons when the ISO is amplified   Any ideas? Thank you very much.
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My understanding of the ISO setting on digital cameras is that, unlike film-cameras, changing the ISO does not evoke any physical change in the camera.  Rather, it simply tells the camera to multiply the analog-voltages it reads from the sensors by a constant number, which increases the brightness of that pixel in the output JPEG image.  And since the RAW files store the actual voltages read, before any changes to the brightness take place, the values in the RAW file will be the same regardless of the ISO setting.  Thus, if you're snapping pictures in RAW format only, the ISO setting does absolutely nothing (Also it would mean digital cameras with higher ISOs are completely a marketing gimmick).  However,  contradicts that.  It shows the following image:  which claims that the ISO setting does affect the RAW output! †  It also states "to minimise noise get as much light into the camera as possible then use the highest ISO you can without overexposing."  If my understanding is correct, all images with the same shutter-speed will result in the same (RAW) image, regardless of ISO setting.  However, if the explanation in the above post is correct, (RAW) images that were taken with an incorrectly-exposed ISO setting can't be corrected in software without introducing extra noise.  (I found  online in which several 'experts' argue back and forth about which understanding is correct, but never reach a conclusion)    To figure out which understanding is correct, I tried shooting an image at various ISOs and shutter-speeds, in RAW+JPEG mode.  I then loaded the RAW files into Photoshop and applied auto-correct within "Camera Raw" (before the JPEG conversion).    These were the results (click to enlarge):   (All shots taken with Sony a390 DSLR.  Aperture f/5.6, 18-55mm zoom lens set to 55mm)  And for comparison, here were the JPEGs created for those same shots by the camera (no Photoshop correction applied):    It appears we're both wrong (What!?!??!!?).  The ISO setting definitely did have a major difference in the final RAW image, but it seems that even when it causes under-exposure, using the lowest ISO setting still resulted in the least amount of noise!!  I assume that, to understand why that is, I need to know exactly how the ISO setting works in DLSRs - could someone please explain that to me?  Is the sensor somehow physically made more sensitive, or is it a simple digital (or possibly analog) amplification of the voltage signal?  Or does it work differently in different cameras (mine is a rather low-tier DLSR)?  If the sensor doesn't physically become more sensitive, why does the ISO setting affect the RAW image?  Why did an underexposed ISO100 image result in less noise (after photoshop correction) than the same image with the same aperture/shutter at (a correctly-exposed) ISO3200?    † (At least, I think that's what he's saying.  The post is ambiguous as to whether the auto-correction was done to the RAW or the JPEG file.  I'm just assuming it was done to the RAW, though, as doing it to the JPEG would just be stupid - he'd be amplifying the compression+quantization noise, not the camera noise, which would make the entire post incorrect)
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This is the Milky Way above Kakadu National Park, Australia, and my first try at astrophotography.    Thirty second exposure, f/4.0 at 17mm with ISO 12800 (!!) which in hindsight probably was way too high and resulted in a lot of noise. I also used Picasa to increase contrast, but I probably went a bit overboard there as well.  , I am looking for input on how to better postprocess this picture to reduce noise.
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I've read through several threads similar to this, but I'm looking for a comparison of two options here.   I currently take photos on a raised glass platform against a white foam board background and run about 300w of lights (3 100x LEDs @ 5000k, Home Depot Specials in softboxes and umbrellas). As you can imagine, it takes me about 15 minutes of post processing to achieve a perfect white background, and sometimes I have a particular photo that I am unable to get there.  I want to upgrade to either a photography table with a translucent background that I can place a speedlight under, or a cyclorama infinity background such as the MyStudio MS20. The latter option may require an upgrade to my lighting, which I am planning to do anyways.  The idea of course is to get a blown out 255 background with no post processing, other than color correction on the jewelry or product as needed. This would cut my time after the shoot to a ridiculously small amount of time.   Which option would make my life easier?   For reference, I currently use a D5300 with a Tamron 90mm f2.8 macro lens.  This is the best shot I got after quite a lot of effort, before and after processing:      Note that the silver is not shiny like it should be, and the sparkle on the gems is lost.
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I know digital cameras have ISO options, and that ISO is the camera's sensitivity to light, but if you set  higher ISO then you can get a noisy image. I also know there are two other camera options, shutter speed and aperture.   What is the relationship of between them? Is there any equation, or something like that?  For example, if I set the ISO to 640, then how should I set the shutter speed and aperture?
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I'm very new to digital photography, so I still haven't gotten the hang of all this exposure and ISO stuff, etc. I have a Canon EOS T3.   My question is how big of a difference does it make using manual settings rather than auto settings for everything? I've taken some pretty nice photos with all auto settings, and I'm not sure if it could have turned out any better using manual settings. I know that there are some people who have been in the game for years upon years, and to them they can notice the difference between photos taken with manual vs auto settings, but for my situation, do you think it really makes a difference? Is my camera smart enough to determine the best settings for me?  Also, lets say manual settings are better (which I'm sure they are, since they give you greater control). How often are you supposed to adjust your settings? Between every shot, considering they are unique shots? Or does it not matter about the object, but rather the lighting environment? So if I'm in a forest at 2:00 PM on a sunny bright day and I take photos for one hour, should I be constantly adjusting my settings between every unique shot to get the best out of it? Or do I usually just find one setting that works for the environment I'm in?
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I have seen an "EV" (exposure value) scale that's sometimes used to express a camera's exposure settings, or scene brightness. How exactly does this scale work?
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What is the best way to achieve very long exposures in very bright, sunlit conditions?  Right now, I have a  filter (9 stops reduction), and even with my camera set to ISO 50, and F22, my exposures are still in the range of 5-30 seconds.  Ideally I want at least 1 minute, 5 would be nice. I've had some great (night) shots that involved 800 second (14 minute) exposures.  I've tried stacking crossed polarizers on top of the ND filter, but I get a LOT of vignetting, and the entire affair is rather unwieldy.  Is there a better way to manage very long exposures during the day?  I'm mostly shooting beach scenes, which are generally very bright white. Wave motion in long exposures produces a beautiful hazy effect, that I really like.  B+H produce a 17 stop ND filter, , but I can't find anyone selling it, or find it on B+H's website, for that matter.
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I was shooting the lighting of the city that is visible at the top of the trees if you shoot landscape.  No matter what I do, the image is blurry. What have i done:   ISO 100 Manual focus towards infinity Using a tripod Using really sharp prime &amp; good camera   Basically, everything I could. The only example i have is here, but it is not good, because image is underexposed:    The main question: Why can't night photographs be as sharp as daily photographs (with approperiate exposure times of course)?
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Are more megapixels good?  Are more megapixels bad?  Do more megapixels increase detail? Do they make my images sharper? On the other side, is there a point that is too much? Do megapixels cause increased noise and other problems? How does print and viewing size come into it?  Widespread Internet-forum wisdom used to be that 6 megapixels was the sweet spot — below that just wasn't enough, but above that, there wasn't much benefit. File sizes got larger, but detail was lost to noise and other problems. The arguments are that cramming too many pixels into a small sensor makes each pixel too small to provide any real benefit, and that higher-megapixel sensors outresolve cheap lenses anyway. (Substitute something like 12 instead of 6 if we're discussing APS-C DSLRs, or 24 for full-frame.)  By 2011,  was in the range of 12-18 megapixels. In 2016 most were are in the 16-24 megapixel range. Certainly none are at 6 anymore; even smartphones come with 8 megapixel cameras. Does this offer any real improvement over that old "sweet spot"? Has technology improved to the point where the "wisdom" needs to be updated, or are we all suffering for marketing? Or have we gone past the sweet spot in some ways, but it's okay because of previously-un-argued points. (For example: more noise, sure, but more detail as well.)  Within the 16-24 megapixel common-today range, for the same sensor size, is there any actual benefit to the higher end? How do megapixels directly affect image quality with today's technology? What are the benefits and when do they apply? What are the drawbacks, and when do they apply? How should I adjust my technique (and expectations) based on my camera's megapixel count?
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When should I use exposure compensation, rather than ISO, shutter speed or aperture?
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With the release of the Canon EOS R5/R6, there have been many saying that they prefer the 20MP R6 camera over the 45MP R5 camera, due to its lower price but also because of &quot;better low-light performance.&quot; In camera comparison sites, I've also seen the sentiment that bigger pixels (lower resolution) = better low light performance. However, is this a myth? Here is my reasoning for this. Let's say that there are two full-frame sensors, one 20MP sensor and a 80MP sensor. According to many people, the 80MP sensor would be terrible for low-light photography since the pixels are smaller. However, each 2x2 block in the 80MP sensor could be mapped, and in post averaged to a 1x1 pixel, effectively making the image into a 20MP image. This could also be done in-camera as an option. Would this image have just the same amount of usable information as the image from the 20MP sensor? In other terms, since both sensors are 35mm sensors (i.e. equal area), the amount of light falling onto the sensor is the same. So, at the end of the day, there will be no difference between a 20MP image and a 20MP image that has been downsampled from 80MP, right? So their low-light performance would be the same. You even get an advantage from having the option to get 80MP photos if you wanted. Why do people say that a lower-resolution camera has better low-light performance, when it should theoretically be the same as one with higher resolution (all other factors equal)? Note: this question is about sensors with the same size but with different pixel density. Hence, it is different from  asking about different sensor sizes. I am aware that a full-frame camera will have better low-light signal due to its bigger area than an APS-C sensor, but what about the similarly sized sensors?
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I unfortunately got a very poor and cheap 18-55mm lens on my Canon 60D. In addition to poor quality of my photos (poor in comparison with my 50mm f/1.8 Lens which makes great pictures) the noise level of my pictures is really high.  Should I upgrade my camera or get a better lens? since I'm interested in "night sky photography" this level of noise is really bothering.  For example you're taking photo of a special scene with two different lenses with the same ISO, Aperture and Shutter speed. Is the noise level of a photo taken with Zeiss Lens the same as Canon Lens?
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I make many product photos for the company I work for. For this I use Canon 400D with two external flash devices Walimex CY-600K.  I've noticed an interesting effect on many of the photos I take with white background. On the resulting image there is a red/blue area visible between object and the background. The effect is strongest for black objects and also seems too decrease when I make a brighter photo. It is mostly visible only if zoomed in really close and is not a real problem for me as the resolution is quite high and the resulting images are only 500px wide.   I am just curious as to what is causing it exactly.   For the following example photo I used manual mode with these settings: 1/200 F10 ISO200:  .  You can see blue area left from the object and red area right from it. What is causing this?
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I am trying to figure out why JPEG compression causes noise in the red spectrum that is larger and fuzzier in regards to, say, the blue spectrum.  I've seen  and I am not looking for a workaround; I just want to know why red is prone to more distortion during compression.  This behavior is highly visible in 'political campaign' images (where the picture is rendered in red, blue, and some shade of tan), but is visible elsewhere too.  Here is an example:  Notice the border along the red side?
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I know that this effect occurs when there's a shallow depth of field.  My question is, what are the various ways I can increase this effect in my photos when I'm taking them?    Note that I'm not asking  how to use an editing program to achieve this effect after in post production or after the image is captured.
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Picking up from this  and this , What exactly is ETTR? How it may reduce the image noise? And how is it difference from film to digital sensors?  In the answer linked above, what are the 5 stops and is it related to ETTR?  In real life how can I apply this technique when I'm shooting?
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I'm trying to see how  correlates with practice. That answer basically says I need to let enough light into the camera and then use the highest ISO value and I'll get the lowest noise then.  So I make two shots with the same camera. Camera has aperture set to a specific value, fully manual mode, camera is on a tripod and focused onto a specific faraway object. Shooting is done around midnight, so it's rather dark. The scene is a large industrial building standing faraway across a field from the camera. The field has no light sources, all lights are on the industrial building.  I dunno if it's important but images are written as JPEG inside camera - no shooting to raw and external post-processing. Maybe that's why I see my unexpected result.  Camera highest ISO value is 3200 (not using extended ISO values).  So I first shoot with ISO 1600 and shutter speed set to 1/125 second and then I shoot with ISO 3200 and shutter speed set to 1/250 second. The amount of light should be identical and indeed both shots look properly exposed and exposed the same way.  When I open the pictures in an image viewer and zoom in to one hundred percent  I see that ISO 1600 shot is much cleaner than one with ISO 3200. I checked that several times and I'm sure - it's not the other way around.  Why is this? Is this because of post-processing difference?