Focal lenght and shutterspeed

[loebas]

After reading some threads I'm a bit confused about what is true.
Suppose you have a 70-200 lens.

General rule is that yuo use a shutterspeed of 200 ore 320 (200x1.6)
what confuses me is do you need this shutterspeed on all focal lengths or just when zoomed at 200mm.
(so at 70 mm you can work with a shutterspeed of 70)

Am I wrong ?

[PacAce]

No, you are correct although the 1/focal length ( X 1.6) is just a rule of thumb. Some people can go slower and others need to go even faster.

[loebas]

No, you are correct although the 1/focal length ( X 1.6) is just a rule of thumb. Some people can go slower and others need to go even faster.

To be sure: when on 70mm you can use shutterspeed of minimal 70

[cmM]

yup

[Pekka]

See http://photography-on-the.net/forum/showthread.php?p=385858#post385858

[mbze430]

unless you have a very steady hands, you can go 1 stop slower. but generally speaking that's the rule of thumb

[SeanH]

70MM......X 1.6 = 112.....125th Min. shutter speed
200MM....X 1.6 = 320..... 320th Min. shutter speed

Hopefully that make's it very clear.

[cmM]

70MM......X 1.6 = 112.....125th Min. shutter speed
200MM....X 1.6 = 320..... 320th Min. shutter speed

Hopefully that make's it very clear.
No offense but..... how did you get to the conclusion that crop factor applies for "handholding"? I just don't see the logic.

[robertwgross]

No offense but..... how did you get to the conclusion that crop factor applies for "handholding"? I just don't see the logic.

cmM, let's not get into that again. This logic has been beaten around time and time again. The consensus (at the end of the last go-round) was that the 1.6 factor applies to the focal length. That is, for a 200mm lens, the "effective" 320mm (based on the field of view) dictates a shutter speed of 1/320th or faster.

Of course, in the morning when Belmondo has just had his coffee, he has to shoot it at about 1/1000th.

---Bob Gross---

[cmM]

...OK, let's not... even though I have a very compelling argument that that's just plain wrong.

[robertwgross]

...OK, let's not... even though I have a very compelling argument that that's just plain wrong.

You may have a compelling argument, but so have others in the past. Once you think about the field of view, being 320mm in the example, you will agree. You know that riots will break out if this gets brought up again! We shouldn't have to re-hash old discussions.

---Bob Gross---

[Belmondo]

Bob is right.

Save your compelling argument, though, becasue this topic will come up at least a dozen times in the next month.

[robertwgross]

Save your compelling argument, though, becasue this topic will come up at least a dozen times in the next month.

Belmondo, I've warned you forty million times never to exaggerate.

---Bob Gross---

[Belmondo]

I'm sure you have, but I lost count after twenty million.

[cmM]

then perhaps someone will be kind enough to point me to the merry-go-round debates about this, so that I may agree...

[Belmondo]

Here's one discussion. There are others.

http://photography-on-the.net/forum/showthread.php?t=56402&page=1&pp=20

[cactusclay]

I agree, I think. well, whatever they said, then again on the other hand. Wait, what was the topic again?

[cmM]

yup, that's merry-go-round allright... someone replied to that "there is no real answer", to which I totally agree.

Tom, your point is valid, IF you magnify that image by 1.6, but that doesn't mean the 1/focal length rule becomes a 1/(focal length*1.6) rule because you won't always magnify the images coming out of a 1.6x camera.
Camera shake will be the same whether you take a picture with a 1Ds+200mm or a 20D+200mm. Now how noticeable the camera shake will actually be that depends on the size of the pixels themselves, sensor, etc...

[Belmondo]

The fact is, we're all saying the same thing, but articulating it differently, and maybe even putting some factors in that really aren't in the question.

You are right. Camera shake is going to be the same through a 200 mm lens whether it's being recorded on an APS sensor or a full-frame sensor.

The shake is magnified when the recorded image is magnified 1.6X to equal the size of the 24 X 36 sensor. When that happens (and this is the part that really isn't part of the question) the image is magnified 1.6 times, and the effective shake is magnified by the same amount.

So you are right....

And I am right....

When we can agree on the proper premise for the how the question should be asked in the first place, then we can agree on the answer.

If we could just content ourselves to say that smaller sensors result in cropped images, the answer would end right there. Camera shake will be the same.

It's when we start getting into this idea that some sort of mysterious magnification takes place with smaller sensor that we have to start redefining what logic tells us should be the case.

[RJSorensen]

Higher shutter speeds are working for me . . . but I was hard pressed to use them. It is hard to change style . . . thanks for the help these type threads bring to light and share.

[robertwgross]

RJ, we're going to get you up to about ISO 1600 one of these days.

However, you won't get me up there (My D60 only goes up to ISO 1000).

---Bob Gross---

[Persian-Rice]

On the 1DMKII I can shoot Junior A level hockey (very fast paced) at 200mm at approx low 200 and get no blur, to be safe though 300ish is usually the safest.

[CyberDyneSystems]

Belmondo, I've warned you forty million times never to exaggerate.

---Bob Gross---

ROFLMAO

Cmm,

I'm sure you've seen this;
http://photography-on-the.net/forum/showthread.php?t=45388

But more specifically,. did you read this thread on the 1/1 focal length "rule";
http://photography-on-the.net/forum/showthread.php?t=48748