The F8 rule: doesnt work for me

[sincere]

I tried this F8 thing that supposedly gives you better pics but in order for me to even see something, i have to crank up the ISO and shutter speed something serious and then the pics are super-grainy (because of the ISO obviously) - did i misunderstand something about this rule?

 

[tirediron]

Sorry, what F8 rule? What are you trying to shoot, and what are the circumstances?

 

[sincere]

THIS. I mostly shoot street, things i see so i have to react fast.

 

[Light Guru]

I tried this F8 thing that supposedly gives you better pics but in order for me to even see something, i have to crank up the ISO and shutter speed something serious and then the pics are super-grainy (because of the ISO obviously) - did i misunderstand something about this rule?

Well you cannot just set any lens to f8 and expect magically sharp images. Every lens is different and so f8 is not going to be the sharpest aperture an all lenses. If f8 is going to give you to slow of a shutter speed then why stick with f8. Digital noise from high ISO is different from camera to camera also some cameras do great with high ISOs and some cameras do poorly with high ISO.

Basically f8 is NOT a rule, its a suggestion that may or may not work depending on what you are shooting, and what you are shooting with.

 

[pgriz]

What kind of camera do you have? Most modern digital cameras (DSLR) acquire focus wide open and snap to the set aperture only at the point of exposure. For that reason the manufacturers have added a preview button that allows the aperture to close so that you can judge the depth-of-field (kinda - doesn't work very well). As for f/8, it is considered "good" because it is more-or-less the mid-point of the aperture range and for many lenses, that's where they are sharpest. In addition, f/8 for most apertures gives enough depth-of-field to be relatively tolerant of focusing errors with focal lengths below (about) 100mm. If you follow the sunny-16 rule of exposure for bright sunshine, you'll be using at ISO 100 exposures at f/8 and 1/500 sec. Cloudy is about 3 stops darker, so you'd have exposures of ISO 100 / f/8 / 1/60 sec. Tell us your typical light conditions and the exposure settings you're using.

 

[sincere]

I have a Ricoh GR - 18mm (fixed) 2.8 - what would be the equivalent to F8 with my lens? I just want to understand wtf this blog is talking about

 

[tirediron]

Ahhhhhhh... the old "F8 and be there!" rule. First, remember that dates back to the days of the Speed Graphic 4x5 press camera, and was important mainly because the cameras of the day didn't have the focusing flexibiltiy that modern DSLRs have. F8 was chosen to give a reasonable depth of field, and was also often used in conjunction with flash. With a modern camera, you will be much better off becoming familiar with DoF tables and setting an aperture approriate to the situation.

 

[480sparky]

F/8 is f/8 is f/8, regardless of the lens, focal length, manufacturer, format, race, creed, religion, national origin.......

But the nothing magic about f/8. It's only one of many choices on most lenses. Some lenses are sharp as a tack at f/4 or f/5.6, but start to get into diffraction by f/8. Some are superb performers at f/8, suffering soft corners when opened up, and the dreaded diffraction when closed down more. Others still can improve over f/8 at f/11 and f/16.

And some lenses are soft no matter what aperture used.


Photography is about choices and compromises. One just cannot say, "I'm going to shoot everything at ISO 100, 1/4,000 sec at f/8 and every image I take will be pin sharp!" The world just doesn't cooperate.

 

[vintagesnaps]

I know that old press photographers' saying too... the point of it was that at f8 you'd have a midrange aperture and could probably get a usable picture. The way I somewhat use it is that I usually leave my cameras set at f8 and 1/125 so when I grab a camera I know that's where it's set (or where it should be set! although I've done it long enough it's a habit now). Then in a couple of turns I can open the lens or close it down a couple of stops pretty quickly as needed.

With your camera I don't know that this type technique would work - I'm using mechanical film SLR cameras and even my digital camera is on all manual settings. So my own variation of 'f8 and be there' works for me but isn't necessarily an option with a camera that I think is a fixed wide angle (with a fixed aperture).

 

[sashbar]

I hear what you are saying, I am using f/7.1 as a default on my camera for steet photography in case I need to react quickly. Not quite f/8 but close. GR is a pretty good camera, so my only suggestion is that you are sometimes shooting in less than ideal conditions with insuffucient light, not fully realising it. With urban light conditions changing from sunny to cloudy and from a sun lit to a shady scene the amount of available light or luminosity is changing dramatically and shutter speed goes from 1/500 to 1/125 to 1/60 very quickly. The reason for f/8 is to be quick with a fast moving subject/scene. And for a moving subject 1/125 is often too slow. So it is either high ISO or, if your Ricoh is not good at it, you have to be sensitive of light and see the change when you move from a brightly lit scene to a shadow. Naturally humans underestimate the changes of luminosity due to the way our eyes adapt to it, so we need to make a concious effort to monitor it and adjust camera settings.

 

[Joves]

I used to shoot with an old Graflex Crown, and having it at f/8 left you a good amount of room to play with. With the newer cameras use whatever the will get you the shot in the light you have. I still use f/8 out of habit mostly. But I do not just leave it there. You have many aperture choices for a good reason use them to get the effect you want, and the shutter speeds you want.

 

[sincere]

Ahhhhhhh... the old "F8 and be there!" rule. First, remember that dates back to the days of the Speed Graphic 4x5 press camera, and was important mainly because the cameras of the day didn't have the focusing flexibiltiy that modern DSLRs have. F8 was chosen to give a reasonable depth of field, and was also often used in conjunction with flash. With a modern camera, you will be much better off becoming familiar with DoF tables and setting an aperture approriate to the situation.

I just looked at DoF tables or better yet calculator and i am not sure how to read this stuff properly because it doesnt say anything about shutter speed. check it yourself: Depth of Field Table

 

[weepete]

Dof calculators and tables have nothing to do with shutter speed. The are there to help make sure you dof is large enough to cover your subject. What the table is gving you is the near focal limit and the far focal limit for you apeture choice and distance to subject.

Eg

From the table: at distance of two feet from your subject at F1.4 nothing will be in focus for 1'11.9" then you will have a slice of focus until 2'0.1" and everything beyond there will be oof. your slice of focus will be 0.2" wide.

Normally DOF calulators will also give you a hyperfocal distance, which is the distance to your subject required for maximum DOF at any given apeture
and focal length

 

[JTPhotography]

Ignore these "rules". Practice like hell and learn your fundamentals, then every singe time you set the camera's aperture, shutter speed, or ISO, you will be doing so for a specific reason, and you will control the outcome of your photos. There is no easy way around it.

 

[bratkinson]

F/8 is f/8 is f/8, regardless of the lens, focal length, manufacturer, format, race, creed, religion, national origin.......

But there's nothing magic about f/8...

Sparky hit the nail on the head. f8 is f8. F8 will get you a reasonable depth of field for most subjects, and be reasonably sharp. But you have to know what other compromise settings that need be made and what the tradeoffs are.

But beyond that, the first rule of photography is 'there are no absolute rules'. There's 'rule of thumb', 'rule of thirds', 'rule of <whatever>' ad nauseum'. They are all merely starting points, not solutions. As several have responded previously, most (but not all) lenses are sharpest somewhere near the midpoint of their aperture range. Using f8 will often be very near the sharpest aperture for many lenses...but some, f4 or 5.6 or ... Even reading MTF charts until you are blue in the face for a particular model lens may not accurately reflect the copy of that lens you have on your camera. Anything mass produced is always subject to some variations. Lenses and cameras are no different.

While having a starting point is always useful, knowing where to go from there to get what you want is far more important. That's why I love digital photography vs 40 years or so of shooting film that I did previously. Instant results. I can see what I got, and if needed, make some adjustments and shoot again. As someone on this forum mentioned several months ago, photography is the process of making 'an acceptable compromise' between each part of the exposure triangle and the resultant benefits and losses of each adjustment. Oftentimes, there are multiple combinations of aperture, shutter speed and ISO that will result in a proper exposure. The difference in results can be quite dramatic between wide open aperture at f1.8 vs f22, for example, or 1/10th sec vs 1/1000th shutter speed. KNOWING what the effects of each setting increase/decrease is the whole basis of producing good pictures in just about any lighting situation. Some lenses are incredibly sharp wide open at f2...but most are not. At f2, the depth of field is often exceedingly thin for close in subjects. If highly out of focus background (even an inch or two from the subject) is not what you want, then f2 is not the setting you want.

It's all about knowing the exposure triangle to the point you need not have to consciously think in specific settings, it becomes automatic. I typically think only in terms of faster/slower (to 'freeze' the subject or not) or wider/narrower (DOF), from some starting point and make my settings from there. That starting point may simply be whatever the previous frames were shot at. It may be the result of putting the camera in "A" mode and see what the camera decided it wanted. Needless to say, I'm the kind that doesn't follow any 'rules', per se. I simply start somewhere and go from there with whatever lighting I am dealing with.