September 23, 2014, 06:55:51 PM

Author Topic: aperture!  (Read 4279 times)

Pi

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Re: aperture!
« Reply #15 on: September 20, 2013, 12:14:23 AM »
If you want the maximus possible sharpness in your composition use the list in the following page so that you do not suffer from the negatives of the defraction limited aperture (last column)

http://www.the-digital-picture.com/Canon-Lenses/Field-of-View-Crop-Factor.aspx

While it’s helpful to know your cameras DLA, that only tells you when diffraction starts becoming a factor, for your camera.  The lens that you use will have a sweet spot as well.

DLA is as meaningful as noise per pixel level, or how camera shake affects pixel sharpness; in other words, do not worry about DLA.

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Re: aperture!
« Reply #15 on: September 20, 2013, 12:14:23 AM »

RAKAMRAK

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Re: aperture!
« Reply #16 on: September 20, 2013, 09:07:31 AM »
The OP mentioned HFD and in my replies I kept on keeping it in the discussion (although I myself never use it as I cannot remember what the HFD for any of my lenses at any aperture size). So I stop down to f/7.1 or f/8 and focus on the subject that I want to be sharpest. Then whatever sharpness I get is acceptable to me. I thought if I could use HFD all the time then I would get even more sharpness, but that does not appear to be the case.

I found this nice article on NorthLight..... it might be interesting to many of us here.

http://www.northlight-images.co.uk/article_pages/hyperfocal_distance.html
« Last Edit: September 20, 2013, 09:22:22 AM by RAKAMRAK »
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AlanF

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Re: aperture!
« Reply #17 on: September 20, 2013, 11:07:00 AM »
If you want the maximus possible sharpness in your composition use the list in the following page so that you do not suffer from the negatives of the defraction limited aperture (last column)

http://www.the-digital-picture.com/Canon-Lenses/Field-of-View-Crop-Factor.aspx

While it’s helpful to know your cameras DLA, that only tells you when diffraction starts becoming a factor, for your camera.  The lens that you use will have a sweet spot as well.

DLA is as meaningful as noise per pixel level, or how camera shake affects pixel sharpness; in other words, do not worry about DLA.
The 60D crop has DLA of f/6.9. You can see a real difference between f/4 and f/16 for, for example, the 70-200mm f/4 IS, which is very sharp at 200mm and f/4.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=736&Sample=0&FLI=3&API=0&LensComp=404&CameraComp=736&SampleComp=0&FLIComp=3&APIComp=5

Moving to FF with a 1DsIII with DLA of f/10.2, the difference is less.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=453&Sample=0&FLI=4&API=0&LensComp=404&CameraComp=453&SampleComp=0&FLIComp=4&APIComp=5

Slrgear.com gives very nice plots of how increasing f number above the DLA causes increased blurring. However, the effects become most noticeable when cropping small areas, which is not usually done for landscapes.
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jimjamesjimmy

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Re: aperture!
« Reply #18 on: September 20, 2013, 12:48:20 PM »
ok now im really confused!

looks like im gonna  have to take a lot of multiple images with all the different f numbers with and with HFD/infinity focus and see what works best for each particular composition!  seems like the only way to find out!



privatebydesign

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Re: aperture!
« Reply #19 on: September 20, 2013, 01:02:12 PM »
ok now im really confused!

looks like im gonna  have to take a lot of multiple images with all the different f numbers with and with HFD/infinity focus and see what works best for each particular composition!  seems like the only way to find out!

The best way, without tilt, is to combine the two techniques. Focus close to infinity but well within the figure HFD calculations suggest. Try it, it works.
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Drizzt321

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Re: aperture!
« Reply #20 on: September 20, 2013, 01:03:52 PM »
ok now im really confused!

looks like im gonna  have to take a lot of multiple images with all the different f numbers with and with HFD/infinity focus and see what works best for each particular composition!  seems like the only way to find out!

Yup! Best thing is to just go out and take pictures. Stats & specs & calculators are aids, but nothing compares to actually taking photos and deciding what you like best.
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golubiewac1

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Re: aperture!
« Reply #21 on: September 20, 2013, 05:02:05 PM »
Experimentation is great.  That way you get a feel for how various apertures affect the image using your lens and camera.  But clearly there is a sense of frustration because, while folks understand the principle that a smaller aperture yields a greater DOF the question still remains what aperture do I need to use for this scene that I want to photograph?  I need a number!  I have shared this frustration for a long time and have dealt with the problem by taking lots of exposures at lots of apertures.  Sometimes it works and sometimes it doesn't.  My solution was to develop a set of DOF equations and use them to program a programmable calculator which lives in my camera bag.  So when I encounter a situation that requires special attention to achieving sharp focus on critical elements in the scene I can enter the data into the calculator and get an answer in the blink of an eye.  It works great!  And for those that don't like the conventional values for sharpness, the program includes Circle of Confusion as one of the inputs so you can make it as small as you want.  ( you may not like the results - unless you never photograph anything closer than a mile away or only use ultra wide angle lenses).  So that's one approach.
Or you can just set your lens to f/8 and have fun shooting.  Most of your landscape pictures will probably turn out just fine.

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Re: aperture!
« Reply #21 on: September 20, 2013, 05:02:05 PM »

RAKAMRAK

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Re: aperture!
« Reply #22 on: September 21, 2013, 04:09:05 AM »
Experimentation is great.  ...  My solution was to develop a set of DOF equations and use them to program a programmable calculator which lives in my camera bag.  So when I encounter a situation that requires special attention to achieving sharp focus on critical elements in the scene I can enter the data into the calculator and get an answer in the blink of an eye.  It works great!  ....Or you can just set your lens to f/8 and have fun shooting.  Most of your landscape pictures will probably turn out just fine.

It might be daunting to some to program their own equations (at least it seems that way to me). But it is definitely a fine way to go if you can do that, otherwise, if you have a smart phone (whether android based or apple's) there are lots of free DOF calculator programs/apps available out there to do the same thing.

f/8 and be there is also a wonderful time tested method.
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RAKAMRAK

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Re: aperture!
« Reply #23 on: September 21, 2013, 04:14:14 AM »
ok now im really confused!



Do not be, set your lens to f/8 - f/11 (whatever your heat desire), focus on whatever you want, and set the camera on tripod. With f/8-f/11 you will need tripod. and fire away.
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Pi

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Re: aperture!
« Reply #24 on: September 21, 2013, 09:53:39 AM »
If you want the maximus possible sharpness in your composition use the list in the following page so that you do not suffer from the negatives of the defraction limited aperture (last column)

http://www.the-digital-picture.com/Canon-Lenses/Field-of-View-Crop-Factor.aspx

While it’s helpful to know your cameras DLA, that only tells you when diffraction starts becoming a factor, for your camera.  The lens that you use will have a sweet spot as well.

DLA is as meaningful as noise per pixel level, or how camera shake affects pixel sharpness; in other words, do not worry about DLA.
The 60D crop has DLA of f/6.9. You can see a real difference between f/4 and f/16 for, for example, the 70-200mm f/4 IS, which is very sharp at 200mm and f/4.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=736&Sample=0&FLI=3&API=0&LensComp=404&CameraComp=736&SampleComp=0&FLIComp=3&APIComp=5

Moving to FF with a 1DsIII with DLA of f/10.2, the difference is less.

http://www.the-digital-picture.com/Reviews/ISO-12233-Sample-Crops.aspx?Lens=404&Camera=453&Sample=0&FLI=4&API=0&LensComp=404&CameraComp=453&SampleComp=0&FLIComp=4&APIComp=5

This example is better understood from "equivalence" point of view. F/16 on crop is like f/25 on FF, which is much more softened by diffraction.

DLA is often interpreted as if you have to open more with higher resolution sensors for better sharpness, which is wrong. It is also often interpreted as a "penalty" of having a higher resolution sensor, which is wrong as well.

A higher resolution sensor would increase more the resolution near the peak, which is around f/4 for good lenses, and less to the right of it (where diffraction dominates) and less to the left of it (where lens aberrations dominate). But that is known and trivial. DLA has no practical value. If your lens peaks at f/4 on 8 mp, it will peak at f/4 on 50mp. BTW, why is nobody worried about the "aberration limited aperture" -  where the resolution is limited by the aberrations?
 


« Last Edit: September 21, 2013, 10:02:28 AM by Pi »

Eldar

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Re: aperture!
« Reply #25 on: September 21, 2013, 05:36:26 PM »
Whenever I am starting out learning something new, I find my self looking for cooking recipes. Cooking, training for a certain race, fly fishing, photography, you name it ...

But the thing is, there is only so much you can get through a recipe. It can put you on a track, in the right direction, with a fair sense of purpose etc. But when you get there, you need to figure out for yourself what it takes to get That picture taken.

f1.2, f8, f22, tilt&shift, focus stacking, shutter speeds, lighting ... they all have their benefits and issues. And for your specific challenge, the only judge is yourself. Get out there, shoot, fail, change, shoot, fail, change, shoot ... and , provided you are persistent enough, you succeed. And the feeling when you nail it ... indescribable :)
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Re: aperture!
« Reply #25 on: September 21, 2013, 05:36:26 PM »