Shutter speed/focal length rule...probable origin

It may have started earlier, but the oft-quoted rule of "minimum shutter speed should be equal to focal length of the lens" thumbrule was codified by "Modern Photography" magazine in an article around 1973. After that article, there was a minor explosion of other magazine writers quoting it.

The venerable "professional amateur" Herbert Keppler did a series of tests with a handheld Nikon F film SLR usingTri-X film through Nikkor f/2.8 35mm, 50mm f/1.8 lens, and 105mm f/2.5mm lenses.

Keppler shot a series of the then-standard USAF resolution target at ten feet and enlarged each frame to an 8x10 print (approximately 8x enlargement), then the Modern editorial staff view each print at normal reading distance.

The average slowest shutter speed acceptable to the jury turned out to coincide numerically with the focal length of the lens.

However, Keppler also did a series tripod mounted to show how tripoded shots whipped the pants off any handheld shots, even at the highest available shutter speeds with any lens.

And he also demonstrated that at greater enlargements, greater shutter speeds were needeed. The shutter speed/focal length rule only applied to 10x enlargement viewed at reading distance.

So where does that leave us? It means most of the time the thumb rule won't suit our purposes. Most of us don't hold as steady as Keppler could and most of us intend to enlarge more than Keppler did. Back in those days hardly anyone ever viewed an image at more than 15x at normal reading distance. These days, we commonly bury our noses into the monitor at 100x.

Most of the "My lens is soft, I must have a bad copy" complaints in web forums are probably subtle camera shake.

Use every trick available all the time. Use the highest possible shutter speed. Use stabilization even at high shutter speeds. Lean on whatever is available. Use a tripod whenever you can.

Another thing to take note of, is that with today's ultra-high resolution cameras 1/SS isn't as effective anymore (unless you've got surgeon-steady hands); I find that with my 24mp D610 1/SS is adequate although I prefer to go a little faster...but on the 36mp D800e 3x as fast seems to be the min I can go to still yield acceptable results (some people say 2x is ok though). I can only imagine what 5Ds users are experiencing.

It is my understanding that the 1/FL was actually originated for medium format photography in the days before the 'miniature format' became popular. So it is interesting to hear something about Modern Photography in 1973 being reason the rule of thumb was quoted so much...having learned photography long before 1973, I distinctly recall following that rule 10 years earlier than that! On that point, I had posted in 2007...

https://photography-on-the.net …/showthread.php​?p=3036019

My belief is the arithmetic associated with FL is in fact some quantifiable percentage of an 8x10" print, which also equates to some percentage of the Angle of View within that print. That percentage of Angle of View applies regardless of the FL of the lens taking the shot. We just happen to associate it with fractions using FL as a convenient memory crutch.

tdlavigne wrote in post #18307518
Another thing to take note of, is that with today's ultra-high resolution cameras 1/SS isn't as effective anymore (unless you've got surgeon-steady hands); I find that with my 24mp D610 1/SS is adequate although I prefer to go a little faster...but on the 36mp D800e 3x as fast seems to be the min I can go to still yield acceptable results (some people say 2x is ok though). I can only imagine what 5Ds users are experiencing.

What's happening there is that people are not sticking to consistent 10x enlargements across the board for comparisons, but making their judgments comparing 100% enlargements of images of different image sizes.

Wilt wrote in post #18307528
It is my understanding that the 1/FL was actually originated for medium format photography in the days before the 'miniature format' became popular. So it is interesting to hear something about Modern Photography in 1973 being reason the rule of thumb was quoted so much...having learned photography long before 1973, I distinctly recall following that rule 10 years earlier than that!

That's why I only claim "codification" for Modern at that time. It's hard to find any earlier reference in print, but there are numerous references after that.

It doesn't seem right to me, however, that it would have originated with medium format cameras as a thumbrule. Most of the medium format cameras being handheld were leaf-shuttered--inherently less vibration--and would have taken less enlargement to 8x10. So acceptable handheld shutter speeds should have been lower than for 35mm.

now I'm not a long time shooter and was born in 73 so anyway...

isn't tech so much better now with IS, etc...

I was screwin around today.. NON EDITED SOOC so it isn't perfect I get it.. but its sharp...

doesn't that negate the 1/ss = focus?

IMAGE LINK: https://flic.kr/p/SyG5​6o

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RDKirk wrote in post #18307495
So where does that leave us? It means most of the time the thumb rule won't suit our purposes.

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I wholeheartedly agree. While it may be an often valid 'rule' for photos taken with shorter focal lengths, it falls apart when one is shooting with a 600 or 800 millimeter lens.

For me personally, and professionally, basing anything on an 8" by 10" print is useless.......what would I ever do with something so small?

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RDKirk wrote in post #18307550
It doesn't seem right to me, however, that it would have originated with medium format cameras as a thumbrule. Most of the medium format cameras being handheld were leaf-shuttered--inherently less vibration--and would have taken less enlargement to 8x10. So acceptable handheld shutter speeds should have been lower than for 35mm.

I somewhat recall reading the statement about the handholding rule of thumb's association with medium format from a reputable, recognized 'expert'. (In fact, it might have been Herb Keppler, in Popular Photography in 2004-2007!) I tried re-finding that reference just now, but was unable to do so. It was made specifically in the context of the 'new' digital format (APS-C), and the modified rule that accompanied it...

Handhold Rule of Thumb = 1 / (FL * 1.6) for APS-C

as being finally getting things back on track after 135 format had already mistakenly adopted the Med Format rule of thumb without modification for the smaller size of the image and shorter FL of the lens to take a comparable FOV.

Via this post, I put forth a hypothesis about handholding speeds for different formats, that the CofC size for the format, and the SIZE of allowable camera-motion blur are in fact related!
I just created a spreadsheet with the hypothetical handholding shutter speeds, assuming that we use a 'normal' lens = 4*Vertical Frame Height and (for the table) assuming we use a short tele of 2* normal. It shows that the amount of area seen within the 8x10 is near identical for all formats, and that the handholding Rule of Thumb is related simply to the FL and

Universal Handhold Rule of Thumb = 1 / (FL * (crop factor*))


*where crop factor arbitrarily uses the 135 format frame height as the universal constant.

All the newbies reading this should fully understand that these numbers are only a GUIDELINE for minimum handheld shutter speeds. I would say that the majority of newer photographers should probably double the suggested shutter speeds until they really learn how to hold a camera steady. That does take some experimentation and practice.

SkipD wrote in post #18307818
All the newbies reading this should fully understand that these numbers are only a GUIDELINE for minimum handheld shutter speeds. I would say that the majority of newer photographers should probably double the suggested shutter speeds until they really learn how to hold a camera steady. That does take some experimentation and practice.

Very true. And, getting back to the (questioned) origins of the Rule of Thumb, one might say that all the resulting values in the table should really be multiplied by 1/(1/0.56), to restore the original margins for error of the original 1/FL equation as it applied to medium format, and get the 135 format rule of thumb to have the safety margin that has been missing for 60 years!

I know, with certainty, that the Rule of Thumb speeds that applied when I was 15-20 are certainly not maintainable 40-50 years later! What would have always worked well at 1/200 with 200mm FL on a Nikon F would occasionally not work today with 200mm on Canon 5DIV -- unless the IS was turned on!

So APS-C with 100mm becomes 1/376 sec., 135 format with 100mm restores safety margin with 1/235 sec. , Medium format (6x6) with 235mm is 1/235 sec. (as the original 'owner' of 1/FL rule of thumb!)

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All the math in the world won't result in a formula that is accurate, because there is one huge variable that is completely random, and cannot be quantified:

Each and every time someone holds a camera, the amount of 'camera shake' that occurs is changing continually. The amount of camera movement right this instant is likely to be very different than the amount of camera shake a half second ago, which in turn is very likely to be completely different than the amount of camera shake one quarter of a second from now, etc, etc, etc.

If one doubts this, just shoot off a 10 fps burst for a full two or three seconds - the results will show a wide range of different amounts of blur, the direct result of completely different levels of camera movement. Our hands and arms are shaky, wobbly things that quiver and shimmer with no consistency or regularity whatsoever.

When camera movement - the major variable - the biggest factor of all - is completely random and changing every nanosecond, math and formulas are really quite useless.

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Rough guidelines like that are good starting points, not hard and fast rules. From what I've seen, most people taking their time can hold a modern SLR stable enough to get an acceptable image with 1/focal length shutter speeds with reasonable length lenses, before IS/OS is considered.

Some can go slower and consistently get an image they consider clean enough for their uses, others need more. And some can settle for nothing less than a large boulder with a 4-20 screw embedded in it as a tripod.


I find that I can get a fair bit longer shutter speeds out of my 7D with a battery grip than I can without it. And I can go to very slow levels with my medium format TLR, however doing so is kind of hit and miss, and subject motion becomes kind of apparent and a bit of a risk in that case.

Luckless wrote in post #18308189
Rough guidelines

i believe it is FoodGuy whose sig line says the answer to any photography related question is 'it depends'

truth.

it wasn't until getting to know what was going on here that I realized that I was pretty damn good at hand holding.

but i for sure enjoy the benefits of IS.

break the rules, or ignore them. a slightly less sharp pic is better than no pic.

Rule of thumb. When I took lessons about 12 years ago (sans IS) the next highest shutter speed of your focal length. So if I'm shooting at 300mm then the next highest shutter speed over 300. Off and I think that is 1/320?

digital paradise wrote in post #18308625
Rule of thumb. When I took lessons about 12 years ago (sans IS) the next highest shutter speed of your focal length. So if I'm shooting at 300mm then the next highest shutter speed over 300. Off and I think that is 1/320?

That would depend on your camera. It took until the 90's before you started to see cameras with dialable shutter speeds finer than 1 stop, so for a 300mm lens you would actually be looking at 1/500, which was the fasted speed on the first SLR that I shot with, or dropping down to 1/250. Even my Pentax ME Super, which was the first camera to be released with an electronic controller, rather than the traditional dial, only allowed selecting whole stops. It did allow for the shutter speed to be infinitely variable when using Aperture priority mode.

I don't know what Minolta with their AF bodies, but I suppose that Canon had the ablity to do intermediate shutter speeds with the introduction of the EOS system, since the control interface has been essentially identical since then, with the front wheel, or two wheel layouts.

Alan