f64 lens ?

[ymages]

is there any (Canon ..or any) lens closing up to f64 ?.. of course for

lanscape

[bobatkins]

If there was you woudn't want it.

 

f64, even on 35mm film would be very fuzzy due to diffraction. On a small sensor DSLR it would be a disaster.

 

The 70-300 zooms go to f45 I think, but only at the long end.

 

Read http://www.bobatkins.com/photography/technical/diffraction.html

[ymages]

ha !? ok ... it was just to know actually only my Canon Macro 180 mm goes to 32

 

thank you

[stephen hazelton]

Good article. The hose analogy is off, but the sample photos are excellent for illustrating the point.

[ymages]

but then how can you get an incredible DOF for landscape with foreground ? ... with top level quality lens ?

[bobatkins]

You can't.

 

Well you can, but you have to take a bunch of shots and digitally stich the sharp parts together.

 

For most people, the DOF at f22 on 35mm film is enough.

 

Lens quality isn't that much of an issue at f22 as long as distortion and chromatic abrreration are low. Other aberrations are minimized by the small aperture and diffraction dominates.

 

BTW the hose analogy isn't scientifically accurate, but for those without a background in math and physics, it's the best way to visualize the situation. Starting out with "Well, if you look at the Fraunhofer Diffraction equations for a circular aperture...." results in blank stares and a tendancy to fall asleep.

[awindsor]

These are done with camera movements. In particular using front standard (or lens) tilt. This tilts the focal plane (by twice the angle of lens tilt). This is called the "Scheimpflug principle". This technically does not alter the DOF but by making the plane of focus more horizontal you get an increase in apparent DOF. In fact you make objects closer to the focal plane.

 

You can do this with a Canon TS-E lens. I somtimes tilt my camera down to get this effect but altering the "film" plane produces perspective "distortion". You can correct this digitally in post processing but you lose picture area.

[rick s]

Want depth of field? How about f/180?<br><br>

Get a <a href="http://www.freestylephoto.biz/sc_prod.php?cat_id=2203&pid=5639">PINHOLE</a><br><br>Yes it's not sharp. It's just the opposite. But it's the most depth of field you'll find, and after all, it's about having fun!

[athinkle]

Sigma 105 macro does f45. I'd hate to see it though, as the aperture doesn't have all that many blades. f16 is good though.

[eos 10 fan]

Would a 1.4x TC make an f/32 lens into an f/45 <br>

or a 2x TC make an f/32 into an f/64?<p>--

[digitmstr]

Macro lenses for 35mm cameras go down to f/32 because at those working distances DOF is minimal as it is. However, the diffraction principle applies when doing landscapes as well as other types of shoots.

[rick s]

<i>>>Does a TC change max Av?</i><br><br>

No...And it's "minimum" aperture that you're referring to, not max. The larger the number, the smaller the opening. Note that f-stop is an inverse number...f/n. <br><br>A teleconverter reduces the amount of light to the film plane (or sensor plane for some) because of the distance it adds. So if you have a f/2.8 lens and you put a TC on there that cuts (for example) one stop, then you are forced to open up by lengthening the shutter speed or increasing your ISO. The TC doesn't actually change the size of the aperture.

[jackflesher]

Pinhole?

[waldo_lee]

The connection between f/64 and DOF in landscape photography relates to view camera work, 4x5 or larger. Speaking generally and without reference to any particular focal length, for 35mm, I'm wary of diffraction at f/16, let alone f/45. Even with 4x5, f/64 is fairly extreme. I used to do a lot of 4x5 landscape work and never once used f/64. Still too much diffraction.

[profhlynnjones]

Bob Atkins is absolutely right, f64 on a 50mm lens would not be sharp because of diffraction (the aperture would be .78mm or .0313" [313 thousandths of an inch). Apertures significantly smaller than an 1/8th of an inch precipitously lose sharpness, not f stop but diameter of aperture.

 

As has been suggested, you can buy a used view camera for anywhere from $250 to $500 bucks and use the front swing of that camera to get "universal focus" in landscapes.

 

Lynn

[bobatkins]

f64 would show exactly the same degree of blurring (loss of resolution as measured in lp/mm) due to diffraction with a 50mm lens, a 100mm lens, a 200mm lens or a 600mm lens.

 

Diffractive blurring on film depends on f-stop, not physical aperture. ANGULAR resolution depends on physical aperture, but LINEAR resolution on film also has a factor of focal length in it and if you do the math you find that things cancel out and that f-stop (relative aperture) is all that counts.

 

There may be some complications due to retrofocus lens design for very wide angle lenses, but in essence the result is the same. It's the f-stop that counts.

 

Tilt lenses are one solution as long as you want focus in a plane (or close to it). You get the same DOF, but you distribute it around a tilted plane, not a plane normal to the camera.

[ymages]

Bob you said: Well you can, but you have to take a bunch of shots and digitally stich the sharp parts together.

 

you mean you take a shot for foreground another for medium another for background focusing each time at different place ?

and you combine the shots in Adobe ? ... all at about f8 ?

[dpowis]

Answering to Eric's last question. That would be "focus bracketing". I think it was first used by people doing micrography (microscope), where the DOF is EXTREMELY narrow. Some people developped software to combine the different planes of focus. I think you can find it readily as freeware on the internet, and I read an article in Chasseur d'Images (the leading French photo magazine), saying it works pretty well for landscape work. That could prove useful if you want to do telephoto landscapes with close and far objects. Although using the different focusing distances could create different magnification ratios for the different pictures.

 

Anyway, hope this helps.

[bobatkins]

Yup, that's exactly it.

 

I don't know how well it works and if the "seams" are visible at all, but if it's done well (and I'd presume it could be with enough effort), it's a way to go to get unlimited DOF at the sharpest aperture without using a tilt lens.

[adrian_seward]

I'm surprised no one has pointed it out yet, but f22 with a 35mm camera probably looks similar to f64 on a 4x5 camera. If you're thinking of ansel adams, f22 on your EOS might get you MORE depth of field than he had at f64 on 8x10 film.

 

as has been discussed endlessly relating to digital camera sensor sizes, the larger your format, the less depth of field it has.

 

This gets complicated, but you can sum it up this way: To obtain the same field of view (the same framing) on a larger format requires a longer lens. (50mm is normal on 35mm film. 150 or so is normal on 4x5 film. 360, I think, is normal for 8x10.) The actual amount of depth of field that you see depends on the _actual_ size of the aperture. However, the aperture is labelled with an f stop, which is a ratio-- it does not tell you what the actual size of the aperture is, it tells you how big it is in relation to the focal lenght. Since the f stop is a function of the focal length, f22 on a 50mm lens is a much smaller hole (50/22) than f22 on a 150mm lens (150/22).

 

So you may actually have MORE depth of field at f22 than f64 on a view camera.

 

As mentioned above, with a view camera the difference is that you can cheat be shifting the plane of focus so that it is NOT parallel to the film plane. Thus you can get part of the frame focused on the foreground and part of the frame focused on the background. This is not more depth of field, it's just a matter of being able to maneuver the in focus area in a strange way.

[ymages]

Daniel : I know Chasseur d'Images and shall have look, I am very interrested

 

Bob : I'll have try with it

 

Adrian : do you know an article for that in detail ?

 

what I would like to know is

what is the best f for best DOF with my :

17-40 f4L

70-200 f4L

180 macro L

ad so on

 

is there any review for it ?

 

 

 

thank you to everybody

[rick s]

Adrian brings up a good point about the difference in lenses, etc. with large format. Was that the point of the original question? Was that the reason for picking "f/64"? I must have missed the specific reference to LF.<br><br>Erick - are you trying to duplicate Ansel type stuff with a small format camera? It's much more than depth-of-field. Adrian is correct about the smaller apertures needed for larger format cameras because a "normal" lens on LF camera is so much longer than a 50mm on a 35mm body (normal is about 135 - 150mm on a 4x5). Longer lenses inherently have shallower DOF. 35mm cameras were originally used for documentary style photography. Yes they can be used for anything, but if you want the sharpness, fine detail, and smooth tonality of something like an Adams or Weston print, then get a 4x5 or 8x10 camera. Of course, how you print and what size also matters. But the fine detail that a big negative can capture will amaze you no matter what f-stop you're at.<br><br>... Thinking about formats, actually with a smaller format digicam you can even get greater DOF than 35mm...<br><br>

Of course we all know the great amount of darkroom manipulation that went into Ansel's prints. As well as the composition, lighting, etc...

[ymages]

thank you RS

 

I'll get a FF next year I hope .. they are really expensive (for me) and I don't like that 5D (except the size) so much

 

non digital camera is nothing for me .. i have no experience with it... i think i'll be better keep on drawing :-)

[rick s]

<i>>>what I would like to know is what is the best f for best DOF with my : 17-40 f4L 70-200 f4L 180 </i><br><br>

I think it's been mentioned (or at least implied) already, but the smaller the aperture, the greater the depth-of-field. But as you stop down further, you'll run into difraction and give up sharpness. Most all lenses are sharpest and perform best around the middle apertures (typically around f/8 for the 35mm format). Like in all photography, you can't have everything. It's all trade-offs and compromises depending on your priorities. Either maximimize DOF by stopping all the way down... or use a middle aperture to maximize sharpness... or find a compromise in between.

[ymages]

I keep in mind Bob solution a panoramic photo, not left to right but foreground to background !

 

I have of course allready noticed that with f8 or f11 i get the best sharpness