High ISO does not seem to be working anymore

kirbclih

New member
Hi,

I was out last night to try and capture the milky way, unfortunately anything above 1250 ISO gave multi-coloured vertical stripes. I've used higher ISO in the past, so have I inadvertently changed a crucial setting or has some failure occurred in my D800?
Regards
Cliff
 

cwgrizz

Senior Member
Challenge Team
Welcome to the forum. I'm not sure on what your problem may be, but did you have the view finder covered with a rag, cover or something. If not, you may have had light sneaking in through the view finder and the higher ISO made it obvious.
 

cwgrizz

Senior Member
Challenge Team
Actually you will probably get better help if you upload a picture to the site showing the stripes.
 

Horoscope Fish

Senior Member
Hi,

I was out last night to try and capture the milky way, unfortunately anything above 1250 ISO gave multi-coloured vertical stripes. I've used higher ISO in the past, so have I inadvertently changed a crucial setting or has some failure occurred in my D800?
Regards
Cliff
Examples would be a big help. As would knowing if you are you shooting JPG or raw.

Have you enabled, or dis-abled, Long Exposure Noise Reduction and/or High ISO Noise Reduction on your D800?
...
 

WayneF

Senior Member
This is not multicolor, but be sure you turn VR off for such work. It's not appropriate anyway, and VR at long exposure at high ISO can capture a red artifact.

800_2084.jpg
 

kirbclih

New member
Stripey one result of ISO 1600, 2nd one was as good as I could do at 1250 ISO
I was shooting with SIGMA 24mm Art lens but I did use 50mm prime just to check it wasn't the lens. I also tried shooting jpeg only, raw only etc.
Also reset one of the shooting banks to default incase i'd messed up a setting.


chk_7864.jpg
chk_7928-3.jpg
 
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The way you processed your photos hides the EXIF data from us. When you say high ISO you listed 1250. Did you really mean 12,500 ISO? It that is the case then that is a lot higher than you should be using for the milky way. Normal range should be around 3200 ISO or so with shutter speed no longer that 20 to 30 seconds. I prefer 20 secs. to process your photos to preserve the EXIF data follow the directions below.

Guidelines to adding a photo to your post.

1. Resize photo to 1000px on the long side.
2. Resolution set to 72ppi (Pixels Per Inch)

These guidelines will be good for viewing on a computer but will not be good for printing. This will help safeguard your copyright.







 
Hi Don,

It was up to 1,250 that would give an image and anything greater than 1,250 would give the stripes

1,250 is not high ISO at all. You may just be underexposing it. Underexposure may cause what you are seeing. What shutter speed and aperture were you using? Like I said earlier ISO 3200 @20 sec at f2.8 is a good starting point. Time over 20 to 30 seconds will allow the stars to move so keep it below that time.
 

kirbclih

New member
1,250 is not high ISO at all. You may just be underexposing it. Underexposure may cause what you are seeing. What shutter speed and aperture were you using? Like I said earlier ISO 3200 @20 sec at f2.8 is a good starting point. Time over 20 to 30 seconds will allow the stars to move so keep it below that time.

I know that 1250 is not high, but that was the highest that would give me an image.
I tried everything from 1.4 to F8 and 6 seconds to 30 seconds. As long as the ISO was greater than 1250 i got the same vertical stripes
 
I know that 1250 is not high, but that was the highest that would give me an image.
I tried everything from 1.4 to F8 and 6 seconds to 30 seconds. As long as the ISO was greater than 1250 i got the same vertical stripes

try shooting in daylight at ISO 3200 and whatever shutter speed and aperture needed to get the correct exposure. See what the results are.
 

spb_stan

Senior Member
Those stripes are more often seen with a failing memory card but it is not the sensor itself since the same sensor is used on lower ISO images. If it does that on all images at higher ISO, even in daylight and fast shutter speeds, it would indicate a problem with the video amplifier that on that sensor is part of the sensor, on the same silicon wafer but off to the side. A sensor has one sensitivity, its base ISO. Higher ISO is gained by amplifying the analog signal of each pixel. With each step increase in ISO the amplification factor increases. To minimize noise, the fewest number of amplification stages are used for the gain developed. Higher ISO require cascades analog low noise amplifiers. It might that that when switching in an addition amplifier at ISO 1600, there is a fault. Another possibility that is related is firmware that controls the switching could be at fault.
To test whether it is related to ISO or time of exposure, try shooting at high iso in normal day time conditions. Does it work OK or now. If not, it is likely hardware amplifier problem, but if it is OK at faster shutter speed, the controlling firmware could be at fault. In that case try doing a full factory reset. That can be done by pressing and holding both buttons that have green dots next to them, for about 5-10 seconds. If that does not do it, try removing the battery and let it sit for a day or two, and reset again. That is a different reset action, using the same two button method.
Do those tests and report back if it only happens at long exposures or if high iso in normal conditions
 
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