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Old Nov 7, 2006, 12:46 PM   #1
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I still have a lot to learn...

What is the meaning when they say that the S.R. can provide 2 stops of handheld advantage? (Please try not to be so complicated) :shock:

What exactly is 2 stops of advantage? If I have no S.R. and no tripod, how muchmust I need to crank up the ISO level in orderto prevent handshaking blur? (In the same lightingcondition as with the S.R.)

Regards.

BTW, anyidea whatis the lowest possible hand holdable shutter speed?



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Old Nov 7, 2006, 1:19 PM   #2
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hmmmm...you seem to know quite abit, how come you don't know this?! I think I understand the concepts so I'll try to explain (someone correct me where i'm wrong!)

ok, say 1/30th of a second at f3.5 is the slowest shutter speed you can hand-hold with a normal camera. With shake reduction you could do one of two things (assuming a gain of 2 stops).

1. you could keep the 1/30th shutter speed, but change the f stop to f5.6 and still get a clear handheld picture.

2. you could slow the shutter speed to say 1/10th of a second, allowing more light into the camera (where there is less available light this is ideal).

I could be wrong with point #1 there, I'm not sure it affects the f-stop values as much as being able to hand-hold at slower shutter speeds.
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Old Nov 7, 2006, 1:35 PM   #3
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I think the inclusion of the aperture valuesare confusing me.

What does the phase "Two stops" means?

What is the value of a "Stop"? In ISO terms?

How doesthe S.R. give a two stop advantage?

If without S.R. & a tripod, how much higher ISO levels must I be using in order to prevent the handshaking blur?

BTW, what is the minimal (slowest) shutter speed that is possibly hand holdable?How is theS.R. goingto help me get the hand holdable shutter speed? (How actually useful can the S.R. be?)

Regards.






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Old Nov 7, 2006, 1:45 PM   #4
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BTW, I am getting confused! :?

Lets see what am I thinking;

I imagine myself needing to use ISO 800 to prevent handshake blur with an F/2.8 lens...IF I fit an F/1.4 lens instead, what willhappen??? What will be my ISO level now??? (I know it will be lower, but at what value?)

IfI added S.R. to my camera...I needed ISO 800 with F/2.8 lens at that situation right? So what happens now that I have added the S.R.? How much will I be able to decrease my ISO level from ISO 800 now that with the S.R. on?

BTW, does the camera noticed that your S.R. is on and will automatically lower your ISO level? (Because it doesn't need such high ISO levels anymore?) Or would it be stupid and still use ISO 800 with the F/2.8 lens in that situation; even when the S.R. could means using a lower ISO level?

Regards.



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Old Nov 7, 2006, 2:08 PM   #5
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Ben,

SR will not automatically lower ISO or any other of the 3 factors controlling exposure.

Exposure is controlled by aperture, ISO and shutter speed

a 'stop' as it relates to ISO is 1 full doubling: 100 to 200 is 1 stop. 200 to 400 is 1 stop. 100 to 400 is 2 stops.

A 'stop' as it relates to shutter speed is also a doubling. So 1/125 to 1/250 is 1 stop. 1/125 to 1/500 is 2 stops.

With aperture the 'stop' progression is 1.0 > 1.4 > 2.0 > 2.8 > 4.0 > 5.6 > 8.0 > 11 > 16 > 22

Now, the concept of anti shake enters in as follows:

Let's say you as an individual can hand-hold a 100mm lens at 2.8 for 1/60 without camera shake (the general guideline is 1/focal length but it is completely dependent upon user and situation).

So, say you are using that 100mm lens and correct exposure is f2.8, ISO 1600 and 1/60.

Now, by saying the anti-shake gives you a 2-stop advantage, the manufacturer is claiming you could reduce your shutter speed by 2 stops (from 1/60 to 1/15) and still get the same quality results. Reducing the shutter speed t 1/15 allows you to EITHER (but not both)
  • change ISO by 2 stops from 1600 to 400[/*]
  • change aperture by 2 stops frm 2.8 to 5.6[/*]
  • change iso by 1 stop to 800 AND aperture 1 stop to 4.0
[/*]
Either of those 3 options give you the exact same exposure with a 1/15 shutter speed as the original 1600, 2.8, 1/60 values.



Now, again let me stress - what you personally can hand-hold a given camera and lens at is something you'll have to figure out for yourself. It differs by photographer. The 1 over focal length is a starting point. But, a photographer with very steady hands may be able to hand-hold a 200mm lens at 1/60 (instead of the 1/200 suggested by this rule).
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Old Nov 7, 2006, 2:18 PM   #6
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JOHN thanks!!! Your explanation sounds professional like with some experience factor(s) in it!

I can't believe how "Powerful" S.R. is!!! What the...Instead of using ISO 1600 without S.R., I can turn down the ISO to 400 with S.R.!! OMG, that's so great!

Thanks once again!

Opps, I have some more questions...:?

Would it be better for me to use larger aperture lenses or S.R.? :-)

So lets say instead of having S.R., I don't want it; but I want to use alarger aperture lens instead, to substitute the S.R....Is that possible? (Would it be a better idea?)

Which lens can provide me with 2 stops advantage? (Or more?)

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Old Nov 7, 2006, 4:42 PM   #7
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BenjaminXYZ wrote:
Quote:
Would it be better for me to use larger aperture lenses or S.R.? :-)

So lets say instead of having S.R., I don't want it; but I want to use alarger aperture lens instead, to substitute the S.R....Is that possible? (Would it be a better idea?)

Which lens can provide me with 2 stops advantage? (Or more?)
There is no right answer to these questions.

a 2.8 lens provides a potential '2 stop advantage' over a 5.6 lens. A 1.4 lens provides a '2 stop advantage' over a 2.8 lens. But with wider aperture you have shallower DOF.

The drawbacks to wider aperture are shallower DOF and size/cost. For instance, most zoom lenses are 2.8 or narrower. So if you want to have something 'faster' than 2.8 that usually means a prime lens. That gets pricey and heavy. And you pay more for a given focal length. For instance the Canon 70-200 f4 is about $650 but the 70-200 2.8 is $1200.

But there is no single answer to which route is better: higher ISO, slower shutter with SR or wider aperture. It depends on many factors.

As you know, I shoot sports. So, to me shutter speeds are critical. So SR isn't much use to me - I need wider apertures and higher ISOs to keep those high shutter speeds. For people that have non-moving subjects and like to handhold, SR is very beneficial. For people that use tripods, SR is not beneficial.



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Old Nov 7, 2006, 5:09 PM   #8
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From my perspective, why compromise? Get both the best of all worlds (high ISO speeds, anti-shake, and fast lenses). :-)

I shoot more people photos than anything else (fishing trips, birthday parties, anniversaries and other family gatherings, live music at low light local restaurants, etc.), and I don't like using a flash if there are other solutions. It's irritating to subjects.

I wouldn't want to be without anti-shake and high ISO speeds.

For example, I've got a dozen or so hand held photos taken just over this weekend at ISO 3200, using shutter speeds as slow as 1/10 second with a KM 5D wearing a Minolta 24-85mm f/3.5-4.5 of friends and family around a campfire (and I don't mind a touch of motion blur when it happens).

I could have used a brighter prime. But, the convenience of a zoom is nice, and I can generally get an acceptable number of keepers at shutter speeds that slow at most focal lengths I'd normally shoot at for the viewing/print sizes I'd want.

Here's one example from around a campfire at a party over the weekend.

Konica Minolta Maxxum 5D, Minolta 24-85mm f/3.5-4.5 at 40mm and f/4, ISO 3200, hand held at 1/10 second. Straight from the camera JPEG Fine with no post processing of any kind. Downsized with Irfanview for Web Viewing and saved at 85% JPEG Quality:


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Old Nov 7, 2006, 6:12 PM   #9
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Same Campfire, same camera and lens.

Hand held at 1/10 second, ISO 3200, 45mm, f/4.5. If you want to capture memories at family gatherings in low light without using a flash, both high ISO speeds and anti-shake are nice to have.



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Old Nov 7, 2006, 6:52 PM   #10
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Yet another... Same Campfire, Same Camera, Same Lens.

Hand Held at 1/10 Second, ISO 3200, 50mm, f/4.5


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