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Archive 2012 · Focus with a UWA lens
  
 
ben egbert
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p.1 #1 · p.1 #1 · Focus with a UWA lens


I have been working on this for a while and have several write ups on my web page about focus technique. It seems each time I get a new UWA lens, I need to learn another trick.

I am a stickler for sharp infinity, and usually hyperfocal does not render distance as sharp as I like. So I usually attempt to get one shot using a distant (mile or more) subject as my focus target. The problem is, the detail and contrast Is not really good enough on a 1DS-mk3 for focus. I have found this true for live view focus or AF confirm.

I often get home with my hyperfocal shots sharp to about mid way into the frame and those focused on an infinity subject out of focus everywhere. The obvious explanation is that I was past infinity.

This issue has plagued me with a 24TSE, 17TSE a 14 Samsung and now a Zeiss 15 f2.8.

I solved the Samyang issue by calibrating the focus dial and setting it strictly on that basis. I can get reliable focus this way. Forget about using live view on that lens and it is not chipped for AF confirm.

I just got my Zeiss 15 f2.8 and did a micro adjust yesterday, it needed +15. That s a bunch and I confirmed it today. But last night I tried a regular landscape and came home with everything oof and the left side the most noticeable. I think I was past infinity again.

This lens is almost at the infinity stop at best focus. So it is not surprising that when you get all the way , you are past infinity, but not enough to make a really blurry image as with my Samsung or Canon lenses. The edges will look worse because the lens is not quite as sharp there as in the center which almost look in focus.

Today I did some hyperfocal research and found that hyperfocal for this lens at f8 and a CoC of .010 is 10 feet. It is easy to live view focus at 10 feet. I did a test shot today in my front yard and with a target of 15 feet (margin of safety) I had a sharp moon even at f2.8. My edges were also sharp. The f2.8 was soft in the lower corners but the f8 shot was sharp everywhere from a leveled camera about 5 feet high.

The technique I advocate is to find a good close focus distance that retains sharp infinity. Then when in the field, use contrasty subjects to focus. Ii works with live view and af confirm.

If my 1ds-mk3 had live view AF, I would give it a try. I did with my 50D and it works fine. But I need the FF for landscapes.

I would love to hear how others get sharp infinity landscapes with an UWA lens.



Nov 02, 2012 at 03:53 PM
gdanmitchell
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p.1 #2 · p.1 #2 · Focus with a UWA lens


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Nov 02, 2012 at 04:23 PM
Gunzorro
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p.1 #3 · p.1 #3 · Focus with a UWA lens


Ben -- Sorry to hear of your troubles with the distant focusing.

I often use the hyperfocal range, but I always hedge inside the max demarcation. Like you, I find it seldom truly sharp at the minimum and maximum areas -- wishful thinking, poor adjustment, or I want too small COC? All the above?

Before I had any live view, using my 5D, I would take a shot, then critically evaluate as best I could at top magnification. That became my sort of funky semi-LV method, and it worked with 24 TS-E for precise focusing. I prefer to set up a twilight shot in bright light before sunset, then fix the lens with a piece of tape (if needed) and wait for the right light.

I also did the same as you, and tested the Samyang until I had precise distances, then remarked the scale on the lens with a new distance scale taped over their setting. Now I only focus by the lens scale, never thru the viewfinder, and it is great.

I have a background in view cameras and folding 120 cameras without rangefinder, so perhaps I am attuned to such methods of establishing the hyperfocal range.

Edited on Nov 02, 2012 at 04:54 PM · View previous versions



Nov 02, 2012 at 04:46 PM
ben egbert
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p.1 #4 · p.1 #4 · Focus with a UWA lens


Gunzorro wrote:
Ben -- Sorry to hear of your troubles with the distant focusing.

I often use the hyperfocal range, but I always hedge inside the max demarcation. Like you, I find it seldom truly sharp at the minimum and maximum areas -- wishful thinking, poor adjustment, or I want too small COC? All the above?

Before I had any live view, using my 5D, I would take a shot, then critically evaluate as best I could at top magnification. That became my sort of funky semi-LV method, and it worked with 24 TS-E for precise focusing. I prefer to set up
...Show more

You understand. I think my solution works, but I need to test it with real landscapes.



Nov 02, 2012 at 04:54 PM
ben egbert
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p.1 #5 · p.1 #5 · Focus with a UWA lens


Here is a link to my webpage with some samples to show what I am seeing. That page also has a link to my SmugMug gallery where full size can be viewed.

Upon closer inspection, I am not sure I was focused past infinity, the grass looks too sharp. In that case it was probably just a case of mis-focus. Regardless of why it was oof you can clearly see that it was in my shot. It was impossible for me to see it at 5x or 10x on the camera so you can see why I don't rely on live view.


http://ben-egbert-photo.com/?page_id=1078



Nov 02, 2012 at 04:58 PM
ben egbert
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p.1 #6 · p.1 #6 · Focus with a UWA lens


gdanmitchell wrote:
deleted


I no longer think it was focused past infinity, it was probably just misfocused, If you see an error in my revised analysis or have a tip I would be glad to hear it.



Nov 02, 2012 at 05:01 PM
Gunzorro
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p.1 #7 · p.1 #7 · Focus with a UWA lens


Right!

And I would be suspicious of your 15mm's MA correction. People like to say that Zeiss ZE have a hard infinity stop, but I haven't always found that to be reliably the case. I'm used to Canon's "beyond infinity" extra focus, so I'm cautious and used to making sure I have established exact focus.

I like to do MA corrections based on actual subjects. In this case (like you) I work at the distance I'll be shooting, or the range of distances. I don't trust the MA taken with test targets at close distance when I am going to be shooting mid to long distances, especially retro focus and UWA designs. Maybe I'm just overly cautious.

From my house in our valley, we have some mountains with fine details like power lines and towers, oak trees on the ridges, etc, on one side about 1 mile away, and on the other about 2.5 miles away, that I use these as my infinity targets (in good atmospheric conditions, of course!). It is a cumbersome procedure, to take a shot, then come inside, evaluate at 100%, then go back and take another shot, and repeat, and again for each distance (I do stack them sometimes with note taking), but when I'm done, the MA is something I can rely on. And at least it is something I can accomplish close to the computer, not out in the boondocks, to return home to unpleasant discoveries.

Anyway, Ben, thanks for your interesting observations and I look forward to your results.



Nov 02, 2012 at 05:07 PM
ben egbert
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p.1 #8 · p.1 #8 · Focus with a UWA lens


Gunzorro wrote:
Right!

And I would be suspicious of your 15mm's MA correction. People like to say that Zeiss ZE have a hard infinity stop, but I haven't always found that to be reliably the case. I'm used to Canon's "beyond infinity" extra focus, so I'm cautious and used to making sure I have established exact focus.

I like to do MA corrections based on actual subjects. In this case (like you) I work at the distance I'll be shooting, or the range of distances. I don't trust the MA taken with test targets at close distance when I am going to be
...Show more

I do my MA exactly this way. I must wait a while to retest the field shot as the sun would be directly in the shot at the moment.





Nov 02, 2012 at 05:12 PM
gdanmitchell
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p.1 #9 · p.1 #9 · Focus with a UWA lens


(EDIT: To clarify, I do my live view focusing almost exclusively at the 10x setting.)

On the off chance that this could be useful... some thoughts about how to use live view focusing.

I've seen people run into problem with live view by looking too closely at the LCD, or even by using a loupe-like device to see it more closely. While some find this effective, I know I'm not the only one who has found that it is possible to end up looking at individual "pixels" on the LCD and be distracted from seeing how those pixels display - or not - an accurately focused image. I know that is counter-intuitive - it seems the you would need to look more closely at this display in order to accurately gauge focus.

But that's not what I've found.

Instead, I pull back a bit from the LDC live view display so that I can get a more generalized view of things and not be distracted by individual pixels. I rotate the focus ring until things are in the right general area. Then I gently rock back and forth across that zone of focus a few times, generally trying to get a sense of the physical feeling of the location of the focus ring as the focus hits the sweet spot. If I look too closely and too analytically, it is possible to get stuck in that loop where it never seems "perfect" - but if I step back a bit, I can find that spot that seems optimal. I also keep in mind that the LCD - at least on the 5D2 - does not have enough resolution to perfectly display the image resolution that the camera/lens system is producing. It is more of an indicator of what is going on than it is a perfect, real display of it.

I generally make an educated guess about which particular object within the frame to focus on. I don't deal with the hypothetical hyperfocal distance stuff - frankly that is obsessive overkill in virtually all cases, and it carries the danger of over-thinking things. So I begin with focusing on something within the frame that seems roughly in the middle of the range of subject elements that I want to see in focus. Once that is accomplished, if the scene contains elements whose distance from the camera varies enough that I think I might be pushing the DOF, I press the DOF preview button and use the 10X magnification to "zoom" around the frame and check focus on both near and far elements to ensure that they will be sufficiently focused for my critical intent. (You must have exposure simulation enabled on the 5D2 in order for this to work correctly.)

There is a notion that one should always pick the "sharpest" aperture in order to maximize potential image sharpness, and this leads some to lean towards, say, f/8 and shy away from, say, f/16. In the real world of big prints, this is unnecessary and may even be counterproductive. Sharpness is always a relative thing. Nothing is ever "perfectly" sharp - even in prints that have excellent sharpness. Depending upon the lens, while the center may be sharpest at f/8, the corners might be sharper at f/11. Or the maximized sharpness at f/8 isn't worth much if you give up sharpness for elements that are further out of the plane of optimum focus by eschewing f/16. Photographically speaking, sharpness is not a purely objective thing - there is an important subjective element to the perception of sharpness and it is not as simple as picking the supposedly "sharpest aperture."

And after making a lot (many tens of thousands) of photographs with full frame DSLRs, I can report that the occasional obsession over avoiding f/16 is unwarranted. Yes, if I don't need larger DOF I may shoot by default at f/8 or f/11. However, I frequently - perhaps most often, with certain subjects - shoot at f/16 and there is no discernible sharpness loss in prints at very large sizes - and there is a gain in sharpness overall in many cases when near and far objects are sharper than they might have been at a larger aperture.

This is true whether one uses live view to focus manually - as I almost always to when shooting landscape and similar subjects - or uses AF.

Dan

Edited on Nov 03, 2012 at 04:04 PM · View previous versions



Nov 02, 2012 at 06:44 PM
ben egbert
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p.1 #10 · p.1 #10 · Focus with a UWA lens


Thanks Dan, I totally agree with your comments on viewing too large and my Hoodman stays in the vest unless I get desparate, but I never thought of your solution and I will give that a try. My vision is best at 12 inches so I do tend to get close so I may need to teach myself something.

I try to have good lenses and most of mine have good corners at f8 if well focused I get enough dof. My main reason for f8 is to avoid dust spots (I get enough at f8) I also practice my focus at f8 and thus only have one aperture to memorize. Stopping down is fine if I need to blur water or something. And DOF just gets better.

I treat hyperfocal as a range limit. That is it gives me an idea on how far or close I could focus and get deep enough dof. I usually do one approx hyperfocal and one near infinity. I guess my new message is that infinity is not a good practice with my current camera and UWA lenses.

I am never afraid of f16 however, but it would not have fixed last nights problem. My f2.8 shot was sharper than my f8 shot. It was just mis focused.

Your 5d-mk2 is actually a lot better than my 1DS-mk3, I know because my 50D is better and I think its the same generation.

I will try your way of looking at the lcd. I still believe that using a closer target that is easier to view will help with UWA.

I now have a 24-70 zoom and the af has been terrific on that lens. I am only having issues wit lenses below 24.

I have shot that same scene with my 70-200 using af on the same tree and got great results. But 70mm magnifies the detail enough to have a decent focus target.

I also think that f2.8 lenses help in this regard when compared to f4 lenses. My 35L and 50 f1.4 are easy to focus but my TSE lenses at f3.5 or f4 are more difficult.






Nov 02, 2012 at 07:03 PM
 

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StillFingerz
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p.1 #11 · p.1 #11 · Focus with a UWA lens


Ben, not sure this will help, but have you looked at something like this viewfinder extension?

VF-3 Universal LCD View Finder
http://www.carryspeed.com/products/lcd-view-finder?fb_action_ids=540660655948221&fb_action_types=og.likes&fb_source=timeline_og&action_object_map=%7B%22540660655948221%22%3A417693851620168%7D&action_type_map=%7B%22540660655948221%22%3A%22og.likes%22%7D&action_ref_map=%5B%5D



Nov 02, 2012 at 08:07 PM
geniousc
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p.1 #12 · p.1 #12 · Focus with a UWA lens


FWIW, I wrote to Zeiss USA complaining about the imprecise infinity stop with the 50 1.4 ZE. They explained that with Canon cameras they have positioned true infinity to be before you hit the actual physical stop because they found that Canon tolerances are all over the place. I have had many Zeiss lenses for Canon and Nikon. Contrary to what Zeiss said, the Zeiss 35 F2 and 21 do focus at infinity, the 50 1.4 ZE is in focus short of infinity as is the 50 ZE MP. The 100MP is short as well at least on my camera bodies. The Nikon ZF2's always seem to be right. Zeiss said that if I send it in they would adjust it. In your case with a really super lens like the 15, I would send it in.

Canon states that focusing past infinity is to cover expansion. I think it's there to cover loose tolerances at least in the case of short primes.

gene



Nov 02, 2012 at 08:46 PM
Rajan Parrikar
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p.1 #13 · p.1 #13 · Focus with a UWA lens


Ben,

Re. Zeiss ZE 15mm f/2.8 -

I found the AF to be unreliable with this lens (on 5D Mark III) given that it beeps over a fair bit of turn of the ring. I therefore did not bother MAing it. This lens is best used with Live View. It promises to be a cracker of a lens!



Nov 02, 2012 at 08:46 PM
ben egbert
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p.1 #14 · p.1 #14 · Focus with a UWA lens


geniousc wrote:
FWIW, I wrote to Zeiss USA complaining about the imprecise infinity stop with the 50 1.4 ZE. They explained that with Canon cameras they have positioned true infinity to be before you hit the actual physical stop because they found that Canon tolerances are all over the place. I have had many Zeiss lenses for Canon and Nikon. Contrary to what Zeiss said, the Zeiss 35 F2 and 21 do focus at infinity, the 50 1.4 ZE is in focus short of infinity as is the 50 ZE MP. The 100MP is short as well at least on my camera
...Show more

I agree on Canon being all over the place. My Zeiss 50 f1.4 has an adaptor and focuses a bit short of infinity. I have never had a lens or camera that could be focus hard at infinity. Now I do. I retested today and found that was the sharpest way to get that picture.

My Canon lenses tend to have lots of space before infinity. This Zeiss lens is close to infinity even when hyperfocused at just a few feet. Makes you wonder why it needs a focus at all?

I am a bit worried about expansion. I bought a 24mm for my Nikon FE 25 years ago and it would not reach infinity. It was a hot day. I went back to the store and they replaced it on the spot with one that did.




Nov 02, 2012 at 09:49 PM
ben egbert
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p.1 #15 · p.1 #15 · Focus with a UWA lens


Rajan Parrikar wrote:
Ben,

Re. Zeiss ZE 15mm f/2.8 -

I found the AF to be unreliable with this lens (on 5D Mark III) given that it beeps over a fair bit of turn of the ring. I therefore did not bother MAing it. This lens is best used with Live View. It promises to be a cracker of a lens!


Thanks, I tend to agree. I retested and got best result with focus tight at infinity.

I tried live view again and once more it was a waste of time.



Nov 02, 2012 at 09:50 PM
ben egbert
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p.1 #16 · p.1 #16 · Focus with a UWA lens


StillFingerz wrote:
Ben, not sure this will help, but have you looked at something like this viewfinder extension?

VF-3 Universal LCD View Finder
http://www.carryspeed.com/products/lcd-view-finder?fb_action_ids=540660655948221&fb_action_types=og.likes&fb_source=timeline_og&action_object_map=%7B%22540660655948221%22%3A417693851620168%7D&action_type_map=%7B%22540660655948221%22%3A%22og.likes%22%7D&action_ref_map=%5B%5D


I never saw this one, but I do have the Hoodman which does a similar job in a less elegant way. I use it mostly to shade the LCD, I find that magnifying the 1DS-mk3 a waste of time, I have even tired it tethered to my laptop. All it does is provide a large grainy image. The LCD needs a whole lot more pixels.


Edited on Nov 02, 2012 at 10:18 PM · View previous versions



Nov 02, 2012 at 09:53 PM
ben egbert
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p.1 #17 · p.1 #17 · Focus with a UWA lens


Update for Dan and others.

If you click my webpage link, you can see more images and also find a link to my Gallery for full size.

My idea to use hyperfocal at a few feet was ok, it made an improvement, but I tried one with the focus dial at the hard infinity stop. That provided the best results.

I also tried Dans idea of viewing from a distance and moving in an out. But at 1X, its like viewing a postage stamp. Everything looks small at 15mm, even real close stuff.

The barn (the subject in question) is so small even at 10X that it is not possible to judge sharpness. I believe the viewfinder is better on this camera than live view.

I suspect this technique works better at 24mm and up or perhaps on a better LCD such as the 5d-mk2.

My hyperfocal technique works pretty good, and would probably print ok if the distance stuff was not primary to the image. But for critical sharpness at a distance, it can be improved.

I often focus stack, and I make several images for the purpose if there is no motion. If there is, I always find the best compromise for processing.

I just want to avoid coming home with nothing usable.



Nov 02, 2012 at 10:03 PM
gdanmitchell
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p.1 #18 · p.1 #18 · Focus with a UWA lens


ben egbert wroteI also tried Dans idea of viewing from a distance and moving in an out. But at 1X, its like viewing a postage stamp. Everything looks small at 15mm, even real close stuff.

Do it at 10x, not 1x. I virtually never try to focus in live view at 1x.

(I see now that I presumed this but was not explicit about it. I've updated the earlier post to avoid confusion.)


Edited on Nov 03, 2012 at 08:37 PM · View previous versions



Nov 03, 2012 at 02:05 AM
ben egbert
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p.1 #19 · p.1 #19 · Focus with a UWA lens


Ok, I thought your overview part was at 1x, I did try it at 5x and 10X but as I said, the details from a 15mm even at 10X are tiny.

That post is pretty visible in live view, but if you looked at the image, everything else is pretty far away.

Maybe this is not a typical landscape, just a place I go for test shots. But the mountains in the background do represent a typical scene.




Nov 03, 2012 at 02:35 AM
ben egbert
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p.1 #20 · p.1 #20 · Focus with a UWA lens


Here is what the LCD looks like on a 1DS-mk3. I scaled this for 3 inches wide at 90dpi.

The first is 1x, the second the barn at 10X. Maybe you guys can see enough detail here for focusing but I can't.

I was looking at that white stripe on the barn edge and it would never get crisp for me at 10X.







1dsmk3 LCD simulation at 1x







1ds-mk3 lcd simulation of barn at 10X




Nov 03, 2012 at 04:25 PM
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