what im trying to find out is when is low light low enough that one needs to break out those 1.XF lenses.....
so far all i
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what im trying to find out is when is low light low enough that one needs to break out those 1.XF lenses.....
so far all i
The answer is going to depend on focal length, your maximum acceptable ISO, subject motion, and AF mode.
There are situations where the scene EV could easily be +5 or more, yet you cannot shoot at f/2.8 because the subject is moving *so fast* any shutter speed slower than, say, 1/1000, would result in blur. Examples: indoor gymnastics, outdoor football at night.
For relatively still subjects, the focal length plays a role because a shorter focal length permits a longer shutter speed; e.g., an EF 24/1.4L can be shot as slow as 1/24 s, but an EF 135/2L cannot be shot at that same speed handheld without some camera shake.
As for sensitivity, your maximum acceptable ISO may depend on your specific photographic needs, such as final print size; it is also dependent on the subject matter, since shadow noise tends to be more prominent than noise in midtones or highlights. And each photographer has a different standard regarding how much noise they are willing to accept--one might accept ISO 6400 for a given scene, another may only accept up to 800.
Finally, for AF mode--if AF is used, some applications such as AI Servo require more light to operate than One Shot. If the scene EV is sufficiently dim, AF may not even be possible without an AF assist lamp such as those found on Speedlites. Canon's stated EV limit for AF is around -1 to 0 EV, depending on camera model, but in practice, I have found that this limit requires a greater degree of subject contrast in the desired AF region(s) than in a higher EV scene.
If we combine all these factors and try to come up with some general guideline, I would say "low light" would be anything lower than roughly EV +2. Examples of exposures for an EV +2 scene would be something like 1/30s @ f/1.4 @ ISO 1600. One *could* shoot it at 1/30s @ f/2.8 @ ISO 6400, but personally, I try to avoid shooting anything beyond ISO 1250. The two-stop difference from f/2.8 to f/1.4, in my opinion, is a lot of additional light-gathering ability. I've used AF assist to shoot in conditions as dark as EV -5. That would be something like 4s @ f/1.4 @ ISO 1600.
For what it's worth, I don't choose to use fast primes simply because I need more light-gathering ability. I often choose fast primes to achieve shallow depth of field.
Quote:
Originally Posted by jks_photo
What if you don't want to just 'get by'? [:P]
I think wickerprints nailed it with the comment that different people and different scenes mean different tolerance for ISO noise, and it's also true that one of the main reasons for using a fast lens is for thinner DoF (and if your main reason is for more light-gathering ability, you sure need to be aware that you're trading DoF for that extra light!).
speaking of tolerance to noise, i have a new appreciation for noise correction software. you could always turn noise into art as shown here:
http://www.google.com/imgres?imgurl=http://www.faderesearch.com/wp-content/uploads/2009/04/digital-noise-bigger2.jpg&imgrefurl=http://www.faderesearch.com/%3Fp%3D353&usg=__u9M14ZTymXc4p243bE5T3VPoT3A=& amp;h=750&w=500&sz=145&hl=en&start =6&zoom=1&tbnid=cEuXoNwJ19ftNM:&tbnh=1 41&tbnw=94&prev=/images%3Fq%3Ddigital%2Bnoise%26hl%3Den%26gbv%3D2%2 6tbs%3Disch:1&itbs=1
[img]/resized-image.ashx/__size/427x600/__key/CommunityServer-Discussions-Components-Files/12/7888.digital_2D00_noise_2D00_bigger2.jpg[/img]
thanks wicker....
yes I guess it all depends on what you achieve with the shot you are making........