Digital cameras: Of image stablizers....
Of image stablizers....
by christy - 12/16/07 6:07 PMJust wondering.... It is nice to have IS on a camera, whatever its form. However, as camera shake goes from slight to heavy, how will IS deal with the problem ? Surely, you cannot set the shutter speed to 1 sec. and expect IS to help you take a good picture. So, what is the threshold of shutter speed for IS to work properly ? Thanks.
christy
Image Stabilization
by snapshot2
- 12/16/07 6:53 PM
In reply to: Of image stablizers.... by christy
Optical Image Stabilization appears to be the most effective type of Image Stabilization.
This type of image stabilization became popular for lenses with longer zooms.
If you hand hold a camera with a 10X lens, you are likely to get a blurred photo due to camera shake.
Because camera shake is amplified by 10 as well as the image.
A tripod is the best solution for camera shake.
But many situations will not let you use a tripod.
Another method is to use the camera viewfinder instead of the LCD.
A camera pressed against your face will help steady the camera.
In addition, lean against a wall, doorway, tree, pole, etc to further steady yourself. Using these methods you can easily take a 10X photo with no blurring.
Two outstretched arms, while using the LCD, invites even more camera movement.
As cameras get small and lighter weight, it is even more difficult to hold the camera steady. A large heavy DSLR camera is much easier to hold steady than a small camera that can fit into your pocket.
People wanting to use a digital camera in low light (no flash) is probably the biggest cause for blurred photos with the small pocket size cameras. To shoot in low light conditions, the camera must choose a slow shutter speed to get a proper exposure.
When the shutter speed drops below 1/60th of a second, camera shake is likely to cause blurring.
Image stabilization can help at 1/30th of a second and even likely to be effective at 1/15th of a second.
Any shutter speed below that needs a tripod.
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There is no threshold. IS will work at all shutter speeds.
by Kiddpeat - 12/16/07 7:43 PM In reply to: Of image stablizers.... by christyCanon usually states that their OIS lenses will provide 2 to 3 more stops of shutter speed. Thus, if you can hold the lens steady at a minimum shutter speed of 250, OIS will allow you to drop the speed to between 60 and 30 while maintaining the same steadiness that you had at 250.
This depends on the focal length you use
by hjfok - 12/17/07 8:15 PM In reply to: Of image stablizers.... by christyTraditional wisedom says you can handhold with minimal blur from hand shakes at shutter speed no less than 1/focal length. The longer the focal length or the longer the zoom, the faster the shutter speed will be needed. Image stabilization can often help to steady the image by 2 to 3 stops as mentioned above. One thing that is not quite clear is whether you need to correct for the crop factor in those digital cameras with smaller sensor size. Since this formula is just a rough estimate and not exact science, you probably should correct with the crop factor (that means use a faster shutter speed).
Seems that...
by Papa Echo - 12/17/07 9:44 PM In reply to: Of image stablizers.... by christyIS is more of a gimmick to boost sales rather than to correct camera shake. Photographers have long survived without it. Sure, for some, it is great to have it. If the 1/f rule is followed, then there should not be any problem - and when IS needs to come into play, you really need a tripod. As you have suspected, IS won't help if the shutter speed is 1 sec. ...(However, there are apperatures which can keep devices, including cameras, 'steady'. This involves gyroscopes, and is outside the scope of normal "IS" )
IS is not gimmick
by hjfok - 12/23/07 1:47 PM In reply to: Seems that... by Papa EchoImage stabilization is definitely not a gimmick. It really helps getting clearer photos, especially if you shoot handheld with longer lenses. But its main value is in taking low light static photos (or low light slow action when combined with a fast lens). I can capture night light as slow as 1/15 with sharp crisp images. And combined with a fast lens and high ISO, I can capture slow action clearly at 1/125 using 320mm focal length. Without IS, there is definitely going to be blurring from hand shake at 320mm focal length. So IS in that case will save the shot.
I shoot mostly handheld, except for the long exposure shots which will absolutely require tripods. Both my general purpose (Canon EF-S 17-55mm f/2.8 IS) and tele (Canon EF 70-200mm f/2.8L IS) lenses have IS. It is impractical for me to carry a tripod (with my 3 year old), so I consider IS essential to my low light photos. Here are a few photos I would not have captured without IS:
http://s165.photobucket.com/albums/u45/hjfok/?action=view¤t=IMG_2212.jpg
http://s165.photobucket.com/albums/u45/hjfok/?action=view¤t=IMG_0940.jpg
http://s165.photobucket.com/albums/u45/hjfok/Share%20Photos%2010-2007/?action=view¤t=IMG_3597-2_1.jpg
http://s165.photobucket.com/albums/u45/hjfok/?action=view¤t=IMG_3047.jpg
Image stabilisation works to a point.
by Dr. Nicolas Rao - 1/8/08 6:22 AM In reply to: IS is not gimmick by hjfokYes! Of course it works. I have been in photography for almost 40 years and back then in the days of film, we could not keep changing ISO's without some kind of compromise in negative or transparency quality. Even in recent times, with film cameras Canon and others had a good IS system in place and at most times, the difference of one stop in speed is all the photographer needs to get that difficult one. Three stops and up to 1/30 of a second would be the safest bet, as I would not use the 1/15 of second with SLR's with a moving mirror for the technical reason that the mirror slap vibration continues all along the frame for that speed. At I/30 of second the mirror slap would be around for only half the frame and at 1/8th it would have died down by that time and that is with a tripod, that is why 35mm SLR's come with mirror lock up, but this feature is found mostly in the pro models. So why IS or better still OIS - It is fantastic considering the number of compact mega zooms that give you 10X - 18X magnifications, which in effect gives you a small camera which would be a fraction of the weight of a tripod, an can most conveniently be hand held by the photographer. At these long focal lengths, OIS is a great blessing as it brings the lens into the realm of practical hand held photography, in places where tripods cannot go! Apart from that even with the dSLr and DSLR's the stabilization improves quality of the shot as ably shown by you.
Weight of the camera needs to be included
by flyingscot4 - 1/8/08 11:02 AM In reply to: Of image stablizers.... by christyWithout IS for many, many years, I was able to hand hold a Hasselblad with a 150mm lens at 1/15 and sometimes down to 1/8 if I had a tree to lean on. With my Linhof 4x5, I could commonly hand hold at 1/8 in ideal conditions. The point is that with my Sony DSC F828 without IS I can hand hold almost as well as I can with my Canon SD800 IS. We all knew that the heavier the camera, the steadier you could hand hold at long shutter speeds. It stands to reason that those of you using DSLR's can do much better than those of us with pocket cameras.
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