What is ISO in photography / digiscoping? Lions in Kruger National Park, South Africa

Essentially, ISO as a camera function describes how sensitive the sensor is to the light that it receives. This means that a high ISO number means that the sensor very quickly gathers information (i.e. allows me to use a fast shutter speed) but because the picture information is gathered so quickly, the smooth quality of the photo is "penalised", introducing more grain/noise in to the photo.
At the opposite extreme, a low ISO gives you great images with very little noise, but you will only have slower shutter speeds at your disposal.

Every camera handles ISO and noise slightly differently, but let's split them generally in to the average compact cameras that are used for digiscoping and DSLRs.

ISO 800 on Canon A590IS. faster shutter speed from the high ISO made this shot possible, despite being at night. Had to sacrifice image quality through noise.

Compact digital cameras for digiscoping: With, by way way of example, a Nikon P6000 or P5100 (both very common digiscoping cameras), using the minimum ISO of 64 gives nice images, but anything above 200 tends to bring a lot of noise in to the images and is then only really interesting for key rare-bird identification photos when nothing else will work.

DSLRs for digiscoping: Entry level DSLRs like the Canon 1000D or Nikon D3000 have effective ISOs going up to 1600. This range is fairly usable, and for various reasons, when using one of these cameras, I would normally start digiscoping with an ISO1600 and drop it down to ISO800 or ISO400 if the light is good enough or I want to try for a better shot of the same subject (i.e. after the ISO1600 shot). The noise at ISO1600 is certainly noticeable in a large print with these cameras, but it really is often necessary to get a fast enough shutter speed for a sharp photo.

ISO100 on Canon A590IS. Low noise. Enough light to still get decent shutter speed.

The noise control of larger DSLRs (e.g. the Canon 7D or Nikon D300s) is considerably better than the little ones, making results at ISO1600 much more appealing. This effect is even stronger with a full format camera (on a TLS800 as normal digiscoping does not work) - the Canon 5D mark II has exceptional noise control and can take some great photos at ISO1600. But even with the Canon 5D mark II, I will normally try to drop the ISO whenever possible.

There is a general rule in photography:
In order to get a sharp photo, use a shutter speed greater than the focal length
i.e. if the focal length is 50mm, use 1/60s shutter speed or faster
if the focal length is 1000mm (as is typical in digiscoping), use 1/1000sec or faster

This rule can be bent a bit, but the more you bend it, the harder it will be to get sharp photos. This is where playing with your ISO will really make a difference.

In video: Swarovski Optik STM80HD spotting scope, 25-50x wide eyepiece, UCA digiscoping adapter, Canon 1000D DSLR

Category:

Howto & Style

Tags:

• ISO
• Lions
• on
• Olifants
• river
• camp
• Kruger national park
• dale forbes
• digiscoping
• shutter speed
• safari
• photography
• savanna
• canon
• 1000D
• spotting
• scope
• telescope
• DSLR

[chrismgpritchard]

Great video, what size lens do you have on?

[digiscopingvideos]

Hi Chris, I happen to just be using the stock-standard Canon 18-55mm zoom; it works quicte well on the UCA adapter with a small DSLR, but because it is rather long, if one wants to use a larger DSLR then it is a very good idea to go for a pancake lens or at least something like the 50mm f1.8.

[AdrianM54]

my teacher thought me this but i forgot it....but now i know thanks 4 the recap :D!

[sasktank]

ISO is light boost

[bratvlad]

So far away from lions :D

[digiscopingvideos]

@ctkallday666, not camera speed, but film speed. In the same light conditions, you could take a faster photo with ISO800 film than ISO100 film, but you have a compromise in graininess. Your t50 should always be set to the ISO value of the film you have in the camera.

With a DSLR, however, one does not have physical film but/so can vary ISO as one wishes, according to what noise/speed compromise you are willing to make at that moment.

[TrueVisual]

Thx! :)

[username1988ful]

nice !!