1/focal length - actual or effective?

TristanP

This may be a dumb question, but when handholding, the mantra is keep the shutter speed 1/fl or faster. For crop cameras, is it the actual or effective focal length? For example, 50/1.4 on a 20D, is it 1/50 sec or 1/80 sec? I'm thinking effective.

Sam

TristanP wrote:

This may be a dumb question, but when handholding, the mantra is keep the shutter speed 1/fl or faster. For crop cameras, is it the actual or effective focal length? For example, 50/1.4 on a 20D, is it 1/50 sec or 1/80 sec? I'm thinking effective.

It's just a rule of thumb. Start out with the conservative 1/80 or more, and see how it looks. Some can hold lower shutter speeds than others. After some trial and error you will get to know what works for you.

Sam

Owen

I try for 1/125 or faster to avoid blur.

Bob&Glennie

TristanP wrote:

This may be a dumb question, but when handholding, the mantra is keep the shutter speed 1/fl or faster. For crop cameras, is it the actual or effective focal length? For example, 50/1.4 on a 20D, is it 1/50 sec or 1/80 sec? I'm thinking effective.

Yes I'm thinking effective too. Go with 1/fl. A 400mm on a Nikon D70 should be hand held at 1/600th sec. On second thought, don't try to hand hold a 600mm lens at all:D

Bob

Nikolai

Actual, period.

TristanP wrote:

This may be a dumb question, but when handholding, the mantra is keep the shutter speed 1/fl or faster. For crop cameras, is it the actual or effective focal length? For example, 50/1.4 on a 20D, is it 1/50 sec or 1/80 sec? I'm thinking effective.

Crop factor only means you're not getting the "whole picture" in 35mm terms.
It has absolutely nothing to do with the practical rules of thumbs developed for the FF 35mm photography.

HTH

HeldDown

Nikolai's got it. Listen to him

zigzag

Actually, everything I've read says Nikolai has it wrong. The accepted method I've read on most forums is to use effective.

I believe the reasoning is that it's like taking a picture with a 35mm camera, then cropping (and enlarging) the shot. If you enlarge, expect to see more effect from camera movement.

I don't even bother to use the rule, but it's been discussed enough on various photo sites that I'm sure that's the answer.

Bob Bell

zigzag wrote:

Actually, everything I've read says Nikolai has it wrong. The accepted method I've read on most forums is to use effective.

I believe the reasoning is that it's like taking a picture with a 35mm camera, then cropping (and enlarging) the shot. If you enlarge, expect to see more effect from camera movement.

I don't even bother to use the rule, but it's been discussed enough on various photo sites that I'm sure that's the answer.

Zigzag, if you have a sharp image at 100% and enlarge it, the image isnt going to show additional movement. Crop is exactly like putting a rectangular mask over the end of the lens, thats it.

Back on topic, the 1/fl really only works for mid range lenses. If you try that with a 300mm or 400mm or longer, you are going to have very few keepers. My goal with 400mm is to be at 1/1000 or faster. The length of the lens, magnifies any vibration. To do that I usually shoot at ISO 400 when its bright outside and use negative comp. That why I have a high level of sharp images then I can get picky with positions of a bird relative to the sun for example.

DoctorIt

I always love when this topic gets dragged up, some people get so excited about it!

It's not a rule, it's just a guideline. I have a friend who can handhold a 200mm lens at 1/60 with great results. I have another friend who couldn't handhold a 30mm at 1/200!


You need to start with a guideline and customize the rule for yourself.

zigzag

Bob Bell wrote:

Zigzag, if you have a sharp image at 100% and enlarge it, the image isnt going to show additional movement. Crop is exactly like putting a rectangular mask over the end of the lens, thats it.

I'll let others argue the point. I was only pointing out what I've seen as the consensus answer to the orignal poster's question, since (as Drit points out) it's been raised a good number of times. I was trying to skip to the end, but I guess you can go the hard way!

wxwax

Bob Bell wrote:

Back on topic, the 1/fl really only works for mid range lenses. If you try that with a 300mm or 400mm or longer, you are going to have very few keepers.

Agreed.

TristanP

Wow, I didn't think I'd start such a sh*tstorm. Thanks for the input everyone.

DoctorIt

TristanP wrote:

Wow, I didn't think I'd start such a sh*tstorm.

way to call a spade a spade! Like I said, I'm always amazed at the controversy a nothing question like this stirs up!

Bob Bell

DoctorIt wrote:

way to call a spade a spade! Like I said, I'm always amazed at the controversy a nothing question like this stirs up!

I don't know if you are pointing at me or not Dr IT:) I just try to help people over come 4-5 years of digital camera misconceptions. But I will stay out of these conversations going forward if you think I help make a controversy.

DoctorIt

Bob Bell wrote:

I don't know if you are pointing at me or not Dr IT:) I just try to help people over come 4-5 years of digital camera misconceptions. But I will stay out of these conversations going forward if you think I help make a controversy.

Don't take me nearly that seriously.

Dispelling digital camera misconceptions is important too. I just like to be the one reminding people that sometimes "rules" which they read about in the beginner photography books are in fact not strict scientific rules, simply guidelines to remember out in the field. And as I pointed out earlier, everyone's "field" is a little bit different. You have to remember that some beginners, depends on their personality, get pretty overwhelmed when they have that book in their hands... "I have to remember 1/focal length... then sunny f/16 too? what!?... Ahhh!!!" (I'm quoting MrsIt directly here ).

Jamoke

Guidelines
Totally a guideline - I've got a crisp sharp picture at 100mm taken at 1/4 second. And I've blurred others at 50 and 1/125. (Talk about a non-consistant photographer....)

The Crop doesn't effect the sharpness of a picture though. Blowing it up (Which crop cameras don't do) does affect sharpness.