# Aperture for total sharpness?



## Jack56 (Dec 24, 2014)

Hi all,
First of all: Happy Christmas!
I want to make a "close up" from a boat (old paint) and a detail of a stone wall. Body mark5dIII.
1. The close up of the boat will be made with the 24-70 2.8 LII. Distance of the subject is about a meter.
What kind of aperture do I have to use for sharpness in the corners?
2. The close-up of the wall will be made with the 70-200 2.8 LII. Same distance, same question.
I tried with f8, f11, f16 but none of them are sharp in the middle as in the corners.

Or, is it better to crop the soft corners? Or .... do I have to use the 100mm L?
Thanks!


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## takesome1 (Dec 24, 2014)

Both of those lenses are sharp wide open.
If I understand it is a boat painting?
If so both surfaces are flat, a deep DOF wouldnt matter.
I would stop down enough to get rid of vignetting in the corners. 
Definitely nothing over f/5.6, at f/16 you are intoducing distortion.

Shoot in live view mode on a solid tripod, 10x magnification and manual focus. Do a 10 second delay.

Not so much on these two lenses, but lenses are usually softer in the corners. Even on these two you will see it pixel peeping.


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## takesome1 (Dec 24, 2014)

Also if you are going to shoot a painting at 24mm you need to PP the distortion out. I found Light Room 5's lens correction does this well.


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## Jack56 (Dec 24, 2014)

Thank you for your reply. It's the site of an old boat , so not completely flat. The stone wall of course is.


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## Busted Knuckles (Dec 24, 2014)

Technically f10 before diffraction consumes the pixel. Visit thedigitalpicture.com for more image comparisions for the corners at various f stops.

However you are fighting field/focus curvature at these distances. A prime of good quality would do much better. Roger C. at lensrental.com did a good job of explaining this.


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## Jack56 (Dec 24, 2014)

I've got the 100mm L. Would that do the job better?


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## dcm (Dec 25, 2014)

Jack56 said:


> I've got the 100mm L. Would that do the job better?



Your problem may be DOF in both photos. Is there a reason for the 1 meter shooting distance? DOF for 100mm lens shot at 1m with f/2.8 is 2cm, f/5.6 is 3cm, f/8 is 4 cm, and f/11 is 5cm. This doesn't allow for much curve which may lead to the out of focus images (center or corners). You will have more options and leeway if you can get farther away. At 2m you have 6cm, 12cm, 16cm, and 20cm respectively. 

100mm focal length should be good on either lens. You might shoot with both so you can evaluate afterwards.


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## martti (Dec 28, 2014)

Getting sharp detail of a flat surface sound like a job for the 100mm macro on a good tripod stopped down to 16 or 22. I know, diffraction. Once you are there, take both and see which one is better. If you really want to complicate the issue, take your laptop along and shoot tethered. On a bigger screen the photo is easier to judge.

If you are having a problem with the corners being soft, why don't you just crop your picture so that you have the super-sharp area. There are enough pixels there unless you are making a mural.


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## Rui Brito (Dec 28, 2014)

Another (strange) idea is focus stacking. Usually for macro use, but...


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## ecka (Dec 28, 2014)

You need to position your camera as precisely as possible, to get the sensor parallel to the flat surface you are shooting, so the DoF plane would cover it. Anything past f/11 is really unnecessary. I would use something in f/5.6-8.0 range, perhaps f/6.3


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## FEBS (Dec 28, 2014)

ecka said:


> You need to position your camera as precisely as possible, to get the sensor parallel to the flat surface you are shooting, so the DoF plane would cover it. Anything past f/11 is really unnecessary. I would use something in f/5.6-8.0 range, perhaps f/6.3



?

Strange. According to my DOF calculation, if OP is 1m from subject, and even if he uses 24mm then everything would be in focus from 0.75m till 1.5m with aperture f/6.3. I think that's to small area to catch the boat or he must really setup his composition that the side of the boat is parallel with the sensor.
If however the OP would take a shot at 2m from object, and aperture f/11 then everything from 1m onwards would be sharp as he has the hyperfocal distance at that moment.


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## Busted Knuckles (Dec 28, 2014)

Before the debate gets too hot. What is the goal of the photo? 

For example if it is to be some sort giant enlargement, then the 90mm TS with the appropriate tilt, a pano set up and as many frames as you want to stitch together is the call of the day. Google "gigapan" for the technique and process, with a special plate called a nodal slider you can do amazing high res single row pans, (turn the camera vertical etc.) the next step after this would be to get a gimbal or full on pano rig to do multiple row pans. 

If it is to compare the lenses, then I would argue the sharpest f stop will vary be each lens but 6.3 is going to be an overall winner. (diffraction limit at the smaller pixel size - IMO would allow for the most precise drawing - could be wrong though). There are pixel peepers on all the boards a plenty who will dissect any photo/lens/sensor combo to such a level that "can't please anyone" comes to mind.

If it is for putting in a picture into a web page to sell either the boat or the wall just about any f stop will work as the resolution of 99.9999% of computer monitors today is 1920x 1080 (2k) or less.

There is a huge amount of technical expertise on the forum, point them (I am a noob) in a direction, before they start feeding on themselves. 

Mike


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## surapon (Dec 28, 2014)

Dear Friends.
I am not the Expert, But I have learn from the PRO include CR. Members all the time.
Here is the great link that we can learn from them

http://www.betterphotography.com/index.php/online-memberships/mclandscapes-sp-6285/free-sample-masterclass/488-knowledge-what-is-the-best-aperture-to-use-article

Enjoy.
Surapon


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## privatebydesign (Dec 28, 2014)

FEBS said:


> ecka said:
> 
> 
> > You need to position your camera as precisely as possible, to get the sensor parallel to the flat surface you are shooting, so the DoF plane would cover it. Anything past f/11 is really unnecessary. I would use something in f/5.6-8.0 range, perhaps f/6.3
> ...



Hyperfocal focusing is a kludge that isn't close to accurate the way we use and enlarge images now.


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## chauncey (Jan 13, 2015)

IMHO...use a prime, tripod mounted lens making sure that you are parallel with the subject at all times>get close enough to make a 
photo-merge with a lot of overlap>before merging, crop away the outer 20% of the images and merge what's left.

The number of images to be merged is totally dependent on the final size desired for the image...
I often wind up with 5-6 foot images of my macro flowers that have been stacked and merged that were taken @ f/8-11.


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## TeT (Jan 13, 2015)

Could we see a picture.

I am thinking that depending upon width of target. You may want to back of a bit more than 3 feet and utilize the zoom a little. I do not remember offhand but doesn't the 24 70 II have a zoom angle/range that performs better to the edges ...

Anyways backing off with f/8 or so will help with the boats curvature by increasing your DOF


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## anthonyd (Jan 13, 2015)

You are photographing a wall with a 70-200 lens from 1m away??? First of all, the minimum focusing distance of this lens is 1.2m, so nothing is in focus at 1m. But even if that was not an issue, how many bricks fit into this picture? Are you sure you can't move back a little bit? As others said before this, moving away will improve your DoF a lot.


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## Halfrack (Jan 13, 2015)

Is the OP trying to recreate the image being linked to?

Proper technique is critical, and shooting from 1m isn't going to give you the results you want. Back up (lots) more, shoot both on the long end of the 70-200, with IS off. Check out http://www.dofmaster.com/dofjs.html


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## jepabst (Jan 13, 2015)

I've always heard that about 2-3 stops closed from wide open, on most lenses, is sharpest.


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## FEBS (Jan 18, 2015)

jepabst said:


> I've always heard that about 2-3 stops closed from wide open, on most lenses, is sharpest.



As a general rule yes, however more and more lenses do no longer follow this rule. the new 400DO II is sharpest at f/4. Only the center of the lens will do even better at f/5.6, but the edges will be less. I don't want to use that rule any longer, just look to the MTF graphs of every lens and do remember or write it down.


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## infared (Jan 18, 2015)

Every lens is different.
I find that it is good to check reviews on each lens that I own so that I can check on its particular characteristics.
For instance...my Sigma 50mm Art is really tact sharp from wide open and only increases very slightly up to f/4.
Most lense are not like that...so it pays to study your equipment.


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## monkey44 (Jan 18, 2015)

For some reason, you all think he's shooting "Flat" - and someone ever mentioned a painting? I believe he's shooting an old boat (with old paint) and a stone wall. Neither of which is 'flat'

So, maybe the OP can clarify here exactly what are the subjects ? That's how I interpret his OP. And possibly, he's shooting longways - along the wall and along the boat - from 1m distant. That is too close for any kind of shot on a boat or a stone wall, unless he is shooting along the side, like a long-shot from prow to stern? 

OP, can you clarify.


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## AcutancePhotography (Jan 19, 2015)

jepabst said:


> I've always heard that about 2-3 stops closed from wide open, on most lenses, is sharpest.



And that is a good general rule and a good place to start. But as others have posted, there are some lenses that will proof that rule.


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