This might be a newbie question but I couldn't find it in past forums. Apologize if it was. I just bought a sb700 and use it with a d3100. I know that the flash and camera "talk" to each other. On auto setting my low light pics are still grainy. I noticed that the ISO was set to 800 automatically. Does the camera not realize that with the flash is doesn't need to be that high? Is the high ISO creating the grainy look? I was shooting with: camera set to auto w/flash, and flash set to TTL. Thank you in advance.
why are flash photos still grainy?
- Thread starter wazari
- Start date
Hello, I'm pretty much a newbie myself but one video that I did watch explained that the higher the ISO the "noisier" or grainy it will look. Try lowering the ISO to the lowest setting and try another one. Here is the link to the video. It explains the settings really well.
Aperture, Shutter Speed, ISO, & Light Explained-Understanding Exposure & Camera Settings - YouTube
Aperture, Shutter Speed, ISO, & Light Explained-Understanding Exposure & Camera Settings - YouTube
Horoscope Fish
Senior Member
If I understand the situation correctly, I think what's happening is this...
You're in full automatic so your camera is metering the shot base on the ambient light and says, "Oh my, low light. Need to crank the ISO to ensure good exposure!" Hence the relatively high ISO and subsequent noise in your shot. Yes, you have a flash attached and the TTL function will do what it can to balance the overall exposure but, and here's the critical thing: it attempts to balance the exposure based on the ISO selected by the camera.
I think the short answer to your question is that your camera can't assess the situation like you're asking it to when using full Auto. You could have controlled the ISO manually by setting it to, say for instance ISO200 or ISO400, thereby forcing the camera to compensate accordingly via the flash output.
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You're in full automatic so your camera is metering the shot base on the ambient light and says, "Oh my, low light. Need to crank the ISO to ensure good exposure!" Hence the relatively high ISO and subsequent noise in your shot. Yes, you have a flash attached and the TTL function will do what it can to balance the overall exposure but, and here's the critical thing: it attempts to balance the exposure based on the ISO selected by the camera.
I think the short answer to your question is that your camera can't assess the situation like you're asking it to when using full Auto. You could have controlled the ISO manually by setting it to, say for instance ISO200 or ISO400, thereby forcing the camera to compensate accordingly via the flash output.
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I would have to agree with Horoscope Fish. When in auto mode regardless if you have a flash or not the camera is going to adjust for ambient light. Being a low lit situation your camera is going to adjust to what it thinks is best. It doesn't know ISO 800 is grainy. All it cares about is that you have correct exposure. The flash being set to TTL is going to fire and the system ( camera, lens, flash) is going to figure out how much light to pump out. If a subject is real close the output will most likely be minimal. If the subject is further away the flash is going to pump out more light trying to light it. Remember when using flash you now have two exposures to deal with. You best bet is to get the camera out of auto to give you more control.
Like the others, I think you are shooting in full auto mode and along with that comes auto iso. On the d3100, you can not manually set iso in full auto mode. You need to shoot in P or Shutter or Aperture priority. Then you can manually set iso. If you really like shooting in auto, try P mode. It is still somewhat 'auto', but you will be able to control iso.
Nikonites Tip #1
If you want to save the exif data. Resize your photo to 1000 pix and under on the long side! The uploaded will auto resize anything larger to 1024 on the long side. But if you allow the uploaded to resize for you it will strip the EXIF. And also tend to muddy your photo.
If you want to save the exif data. Resize your photo to 1000 pix and under on the long side! The uploaded will auto resize anything larger to 1024 on the long side. But if you allow the uploaded to resize for you it will strip the EXIF. And also tend to muddy your photo.
Ok, you have to understand how the Nikon CLS system works to get good flash pictures. When you use a flash, the exposure is NOT determined by the camera anymore but by the LENGTH of the light pulse the flash puts out - it's anywhere from 1/1,000 of a second (for lots of light) to 1/40,000 of a sec when very little light is needed. The way it does that is when you press the shutter, it first puts out a "pre-flash" - a short burst of low level light - the camera than "reads" the light from this pre-flash and based on it's ISO setting, it sends out signal to the flash to adjust the power of the light coming out of the flash and that's how it works. (Notice the hot shoe for the flash is not just one contact but 5 - it's a "signal cable.") It doesn't matter what your shutter speed is or what your aperture is. Your shutter speed will always be much longer than the length of the light pulse from the flash. Your aperture will be used to control the depth of field. Only the ISO matters on the camera. The shutter speed will matter not on the subject but on the background exposure as the flash light is good for only up to about 20-25 ft.
Now, understanding this, this is what you do to get good flash pictures with your flash switched to TTL mode:
1. Set your camera to manual mode - yes do it even if you have always shot in Auto, P, A, or S. Just do it in M!!! Serious!
2. Set the ISO to 200 as a starting point - with the SB700 it's probably good setting for almost all situations.
3. Set your shutter speed to 1/200 and leave it there - remember the "exposure speed" is determined by the length of the light pulse. (If you have seen the hi-speed photos of a bullet going thru an apple, it's taken by the camera "B" - setting, ie shutter just opened and the strobe flash at 1/250,000 sec to catch the image of the bullet - flash photography do not depend on the shutter speed, only on the length of the light pulse.
4. Set your aperture to the depth of field you like - this is your only adjustment. So, for people portraits, set it to f4 or f5.6. Play with it.
Now, with your flash on, take a picture - you'll get great shots. If you want brighter, up the ISO. Also, look at the "+/- EV" adjustment on the SB700, +ev gives you a bright picture, -ev will darken it.
Now, if you are using flash in daylight as a fill in light you can adjust the shutter speed to change how bright or dark your background is - but it will have not much impact on your subject as it's lighted by your speed light which overpowers all the other light. Be care not to set the shutter speed to high, I don't know what the limit for the 5100 but for my 7100, it's 1/250 - above that limit, you'll start to see dark bands across the image - then you'll have to go into the "FP" mode - Nikon's version of High Speed Sync - but that's for Advance SpeedLite class!
Hope that helps.
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Just leave the SB700 at TTL mode.
Yes, same technique for fill light - but feel free to play with your shutter speed - keeping everything else the same, you'll notice the difference in the lighting of the background. Remember the 1/R^2 law - the light power falls off at the Square of the distance - ie 2x the distance, 4x less power, 3x the distance, 9x less power. So, the background will not be lighted by your speed light and the brightness will be determined by your shutter speed (long exposure = more light etc) but your subject's exposure is determined by your speedlights power. When using speed light, your aperture should always be used to control your DOF and not exposure.
btw, here's your picture with graininess fixed - no problem, I shoot at ISO6400 when I shoot events at night where flash is not allowed:
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Oh, one more thing if you are using the SB700 as fill-in flash - set the flash to TTL mode but you have to set the camera's exposure metering to "center weigh" rather than spot. Your SB700 will now be in the TTL-B mode (TTL Background?) It think it's unique to the SB700 - don't know why! Have fun!
In this "leukemia" photo (the first one) you've got a couple of thousand ISO, not 800 (that's how it looks like, judging by it's graininess). Make sure you set ISO manually, and feel free to shoot in all modes other than "Auto+flash" (to maintain the desired ISO value).
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Auto ISO is generally bad news with flash.
Auto ISO makes Manual flash mode be absolutely impossible to use.
If we are using flash instead, we don't need high ISO. Auto ISO can be turned off. The camera still works.
There have been at least three recent methods of how Nikon Auto ISO works with flash, so camera models can act different. The following is speaking of Nikon Auto ISO, in dim places where flash is needed:
In any Nikon DSLR camera model, Auto ISO always remains at Minimum ISO (Auto ISO is not used) WHEN the hot shoe flash (recognized present) is in Manual flash mode, or when using Commander/Remote mode.
Otherwise ...
1. When a TTL flash is recognized as present on older Nikon DSLR models (D700, D90, and D300 and older), Auto ISO usually remains at Minimum ISO (regardless of the ambient, which might be dim, but which is why we are using flash instead). Auto ISO is increased only when the TTL flash limits out on power, and needs the help. Because, routinely, Auto ISO always only triggers at some extreme of whatever available limit exists.
2. But the newer models (D300S onward, D7000, D5100, etc.) begin in dim ambient by first increasing Auto ISO based on ambient, regardless if flash or not (intending to balance flash to the orange incandescent ambient?) So in dim places where flash is needed, the flash is always working into highest ISO. If you don't want high ISO, of course turn Auto ISO off with flash indoors. High ISO means that mixing flash with incandescent lights needs a CTO color filter (allowing Incandescent White Balance to be used), and the newer flashes provide a filter holder.
To determine how your camera model responds to Auto ISO with flash: If with Auto ISO, and if TTL flash is turned on in dim ambient, you see high or Maximum ISO value in the viewfinder, you have this newer version. If you always see Minimum ISO, you have the first version above.
3. The newest models (D800 and D600 and D7100) have changed the method yet again. Auto ISO still uses Maximum ISO with the internal TTL flash (the previous new way 2. above if in these dim places). But if external TTL flash (on hot shoe), Auto ISO is only increased to be two stops above Minimum (if in this dim ambient. Two stops is like ISO 100 to ISO 400, and 400 is very reasonable for bounce). Logic and reason finally won.
So when indoor flash always discovers that it is dealing with high ISO, we can of course simply turn Auto ISO off, and set the ISO we want. The camera will still work if Auto ISO is Off.
I admit that I am not a fan of Auto ISO, especially not with flash, but I understand many people choose to always leave it on. It may cause problems with flash.