Do you prefer f/8 or f/11 or something else?

[ramblingman]

I've seen it here and have read that the sharpest pictures come out between f/8 -f/11. Andy_t just told me this...
Brian,

it seems as if you knew how to use your camera and lens ... then the quality of the lens becomes less important :wink:

Still, it is not a secret that you can use most lenses to good results when you use them within their limitations. 'f/8.0 and you're there' ...

Best regards,
Andy

1. Why is this so?
2. What factors effect choosing one value over the other?
3. What factors effect choosing one value over the other with a particular camera over the other, if this question can in fact be answered?

Thanks!

[Ken Cravillion]

I shoot in low light and I prefer 1.4 and 1.2... :)

[ushered_in]

Different ap. for differents conditions/desired outcomes. You can't just shoot at one ap. and expect every shot to come out sharp. I think I'm the only one posting this cuz everyone is thinking it?

[cdifoto]

I prefer the aperture needed to get adequate shutter speeds. If that means wide open, so be it. This poll and thread is pointless.

[DocFrankenstein]

Depends on the lens you have.

[RodneyCyr]

Informal experiments have shown me that both of my favorite lenses do their best near f/11. For this reason I use the Av mode and f/11 for general walk-around photography, unless the shot requires something different

[ramblingman]

I prefer the aperture needed to get adequate shutter speeds. If that means wide open, so be it. This poll and thread is pointless.

To you this may be pointless because you are more experienced possibly than most. But don't discount someone else's thread who is trying to learn. I felt it was a legitimate question or I wouldn't have posted it. I sure hope your child's teacher never discounts his or her questions. I have heard it here and read most recently in Daniel Lezano's book that Mid-Aperture is to be used when you want the best resolution from the lens - the sharpest being from either f/8 or f/11. Hence, my question. Wide open is to be used when shooting in low light and while handholding to prevent camera shake, as well as for creating a shallow DOF. Small is for extremely bright conditions, you want the background sharp or for macro to give as much DOF as possible, etc.. Blah blah blah, but again, if you shoot at f/8 or f/11, why choose one over the other? Please contribute if you have something constructive to say. Thanks.

[ramblingman]

Informal experiments have shown me that both of my favorite lenses do their best near f/11. For this reason I use the Av mode and f/11 for general walk-around photography, unless the shot requires something different

An honest answer to an honest question. Thank you for sharing what you shoot and why.

[ramblingman]

Depends on the lens you have.

I thought most lenses were sharpest around f/8-f/11? What would dictate that one lens be sharper at f/8 while another at f/11?

[Redbird_xo]

For DSLR, diffraction might come in as early as when the aperture is closed down to f/11. For DSLR, I prefer f/8 over f/11 for all the lenses that I own.

[cdifoto]

To you this may be pointless because you are more experienced possibly than most. But don't discount someone else's thread who is trying to learn. I felt it was a legitimate question or I wouldn't have posted it. I sure hope your child's teacher never discounts his or her questions. I have heard it here and read most recently in Daniel Lezano's book that Mid-Aperture is to be used when you want the best resolution from the lens - the sharpest being from either f/8 or f/11. Hence, my question. Wide open is to be used when shooting in low light and while handholding to prevent camera shake, as well as for creating a shallow DOF. Small is for extremely bright conditions, you want the background sharp or for macro to give as much DOF as possible, etc.. Blah blah blah, but again, if you shoot at f/8 or f/11, why choose one over the other? Please contribute if you have something constructive to say. Thanks.

If you had posed your question in this manner originally, I would have taken the thread more seriously. But you did not.

To answer it as "if f/8 or f/11 were your choices, which would you choose?" then I would say "flip a coin." There generally won't be much difference on most lenses between the 2 apertures, since they are so close together.

Having said that, I pretty much never stop down that far. I don't do landscapes and I don't feel like keeping my sensor that clean. :) My lenses are good enough that f/4 is plenty sharp and usually gives me what I want, excluding those times I need to be wide open @ f/2.8, desperate for light. That doesn't include the Sigma 12-24mm, which is only f/4.5 at 12mm wide open, and f/5.6 at 24mm wide open. I usually go to f/8 for that when I can.

[Miyagi-san]

I'm addicted to fast primes....probably about 85% of my shots are wide open....great for shaky hands, too! :)

[Mark_Cohran]

I thought most lenses were sharpest around f/8-f/11? What would dictate that one lens be sharper at f/8 while another at f/11?

Most lenses are sharpest about 1-2 stops down from full open. That's not f/8 or f/11. To actually determine where the lens is sharpest, you'll need a set of controlled tests that will produce the characteristic curves for the lens. Lens manufacturers publish the theoretical curves for their lenses, so you can use these to get a general idea of where the len's sweet spot will be.

Photojournalist used to say "f/8 and be there" which was the favorite phrase of Weegee. The f/8 was used to get the best balance of exposure (shutter speed) and depth of field in the days of the 4x5 Speed Graphic press cameras.

Mark

[DocFrankenstein]

He still gave you a valid reply - it doesn't matter. You can only shoot at f/11 during the day...

So no matter what lens you have, when there's not enough light you're bound to shoot wide open and disregard the aperture. So while you feel that your question is valid, he's trying to communicate that in the grand scheme of things nobody ever pays attention to that stuff.


To you this may be pointless because you are more experienced possibly than most. But don't discount someone else's thread who is trying to learn. I felt it was a legitimate question or I wouldn't have posted it. I sure hope your child's teacher never discounts his or her questions. I have heard it here and read most recently in Daniel Lezano's book that Mid-Aperture is to be used when you want the best resolution from the lens - the sharpest being from either f/8 or f/11. Hence, my question. Wide open is to be used when shooting in low light and while handholding to prevent camera shake, as well as for creating a shallow DOF. Small is for extremely bright conditions, you want the background sharp or for macro to give as much DOF as possible, etc.. Blah blah blah, but again, if you shoot at f/8 or f/11, why choose one over the other? Please contribute if you have something constructive to say. Thanks.

I thought most lenses were sharpest around f/8-f/11?

Ideally you want all your lenses to be at their sharpest wide open and then you'd want the image quality to degrade because of diffraction as you stop down. That's called a diffraction limited lens and they're very expensive, even if they exist.

Some good lenses, like fast 50mm primes might be sharpest at 2.8 or 2.5 even.

What would dictate that one lens be sharper at f/8 while another at f/11?

I don't have the equipment to test this. I can barely tell if f/4 is sharper than f/22 in most of my lenses and it doesn't affect my photography.

But theoretically, it would mean that the f/8 lens is better.

Seriously though, it all doesn't matter. Use the glass that fits your budget and that can focus fast enough. If you miss focus by 1/3 of an inch, then all of your calculations of "sharpness" have no relevance because the subject is OOF.

[ramblingman]

I pretty much never stop down that far. I don't do landscapes and I don't feel like keeping my sensor that clean. :) My lenses are good enough that f/4 is plenty sharp and usually gives me what I want, excluding those times I need to be wide open @ f/2.8, desperate for light. That doesn't include the Sigma 12-24mm, which is only f/4.5 at 12mm wide open, and f/5.6 at 24mm wide open. I usually go to f/8 for that when I can.

I wasn't being flip when I came up with the question and I discovered the poll, so I'm excited about that because it quantifies the data, rather than having a lot of anecdotal responses. Sorry I wasn't clearer. We're all at different levels and some questions might seem irrelevant to those who are more experienced, but thanks for not leaving me hanging. See, you helped me solidify what I thought I knew, and that is that at the higher apertures, the more you can see filth on your pics - I think this one of the things I learned from your response. I always thought my sensor was fairly clean, but when playing around in adobe, I would notice specks when I changed the color of the background say. Now, I know it's not as clean as I thought. Do you have a way to quickly check the cleanliness of the sensor? Perhaps stop down to f/22 on a white background?

[cdifoto]

Do you have a way to quickly check the cleanliness of the sensor? Perhaps stop down to f/22 on a white background?

Yep. The sky works well enough when it's relatively clear. My sensors are hideous at f/22...even the one I JUST got back from Canon for cleaning. :)

OK so the freshly cleaned one isn't exactly hideous. But it isn't spotless either.

[Miyagi-san]

lol, another reason I leave my lenses wide open....i can avoid the dust and remain in denial :)

oh wait, i forgot that i don't have sensor dust....i forgot my xti cleans it everytime i turn it on :rolleyes:

[ramblingman]

Yep. The sky works well enough when it's relatively clear. My sensors are hideous at f/22...even the one I JUST got back from Canon for cleaning. :)

OK so the freshly cleaned one isn't exactly hideous. But it isn't spotless either.

That's what I've done, shot at the blue sky and checked. Good to know. Now, I'll just have to figure out how to clean it.

[ramblingman]

Most lenses are sharpest about 1-2 stops down from full open. That's not f/8 or f/11. To actually determine where the lens is sharpest, you'll need a set of controlled tests that will produce the characteristic curves for the lens. Lens manufacturers publish the theoretical curves for their lenses, so you can use these to get a general idea of where the len's sweet spot will be.

Photojournalist used to say "f/8 and be there" which was the favorite phrase of Weegee. The f/8 was used to get the best balance of exposure (shutter speed) and depth of field in the days of the 4x5 Speed Graphic press cameras.

Mark

That's what I am talking about, "the sweet spot" like in engines or golf clubs. Perhaps each lens has it's own sweet spot and perhaps figuring this all out will be beyond me for right now. But its seems that if I am doing some walk around shooting, f/8, f/11 is fine and maybe you can't really tell? However, I thought I have seen photos shot at f/11 and 15-30 seconds and they've come out really nice. Take a look at the best night shots thread. (http://photography-on-the.net/forum/showthread.php?t=205834)

[ed rader]

lol, another reason I leave my lenses wide open....i can avoid the dust and remain in denial :)

oh wait, i forgot that i don't have sensor dust....i forgot my xti cleans it everytime i turn it on :rolleyes:

does that sensor cleaner actually work? how long have you had the XTI?

ed rader

[Miyagi-san]

does that sensor cleaner actually work? how long have you had the XTI?

ed rader

:) not sure...i was just being sarcastic. I just got the xti...

I'm one of those that just ignores the whole dust thing until I see it in a photo.

It may work to a certain extent...certainly not like canon's demonstration video lol, with dust particles just perfectly falling off the sensor :p

I'm usually at f1.4-f2.8 anyway....I can't seem to stop down for the life of me :) the search for the perfect bokeh continues,,, :D

[TheGreatDivorce]

I shoot between f/1.2 - f/2.8 probably 85% of the time. f/11 is for weenies ;) JK.

[ed rader]

:) not sure...i was just being sarcastic. I just got the xti...

I'm one of those that just ignores the whole dust thing until I see it in a photo.

It may work to a certain extent...certainly not like canon's demonstration video lol, with dust particles just perfectly falling off the sensor :p

I'm usually at f1.4-f2.8 anyway....I can't seem to stop down for the life of me :) the search for the perfect bokeh continues,,, :D

you'll never achieve bokeh nirvana with a crop camera.

ed rader

[Jman13]

I shoot at whatever aperture gets me the depth of field I want. If depth of field is not important in that shot (flat subject, focused at infinity, etc), I shoot about 2 stops down from wide open. On my first lenses, that was f/8 to f/11. Now, it's between f/3.2 - f/5.6 for most of them. Because most of my lenses are pretty fast, my general purpose 'sharp' aperture is usually f/5.6. When I'm at f/8 and beyond, it's because I want extra depth of field.

[Miyagi-san]

you'll never achieve bokeh nirvana with a crop camera.

ed rader

c'mon man, I JUST upgraded from the 300D.....don't EVEN start helping that voice in my head that keeps dropping hints about how full frame should happen before the end of the year :evil::evil:

:D :D

[farrukh]

Mostly f/8 as its sharper then 11. but when DOF guarantee is requied, I use 11

[wimg]

I thought most lenses were sharpest around f/8-f/11? What would dictate that one lens be sharper at f/8 while another at f/11?
That would be design and implementation, or manufacturing constraints and QC :).

However, most lenses are at their sharpest around 3 stops down from full aperture, and even then it varies from lens to lens. With some it is 1 stop, with some 4.

If you check 50 mm slr lenses, which generally have a Gaussian design, you'll find that they very likely are best at around F/5.6.

Medium to long teles, often at F/5.6 to F/8, unless they are super designs with very good manufacturing constraints. These often do not improve noticeably from full opening. They are often very good from the word go.

WA and UWA lenses are often best around F/8 and F/11, because it is more difficult to fix optical aberrations with these lenses, but often this is also 3 or 4 stops down from max aperture anyway.

The theoretical limit is really determined by diffraction, and the practical limit by optical aberrations. The smaller an aperture gets, the more diffraction there will be. An ideal lens would have maximum resolution at maxium aperture. However, that means large glass and probably a lot of optical elements, all contributing to optical aberrations in some way. Combined they may give better results than separately, though, due to the fact that a fault applied the opposite way of a previous fault may cancel the original fault toa degree.

Anyway, due to the combination of optical aberrations and diffraction, generally speaking the maximum resolution just the lens can obtain, is, due to the laws of physics, about the maximum resolution at F/4, which is around 400-450 lp/mm. However, add a medium to capture that information, and inverse lens laws apply, so that the maximum resolution for APS-C cams goes down to about 40-50 lp/mm for good cameras of this kind. With FF cams it can get a little higher, up to about 80 lp/mm currently.

If a lens persists in having extremely good MTF figures throughout the range from max aperture up to about F/5.6 or F/8, it is indeed a superb lens, very likely built to its maximum practical potential.

Just my ramblings :).

Kind regards, Wim

[Eagle]

Depends on the lens I'm using, the lighting, what I'm shooting, and the background.

[chris clements]

'Prefer" is just a plain silly word to use in this context - no picture-taking circumstances are alike.
Aperture is just one of the variables you must juggle to achieve your required exposure, depth of field and subject movement. Except in controlled (studio) circumstances, esoteric considerations like 'sweet spots' rarely come into play.