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Archive 2015 · Is it me or is it there a lens problem???

billsamuels
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p.2 #1 · p.2 #1 · Is it me or is it there a lens problem???

Also, here's a site that has a decent overview of diffraction... http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm That should explain why digital sensors don't behave like film the further you stop down.

Thanks - that is by far the best explanation of what's going on and why I'm getting poor sharpness at different ISO's & F stops. Great website!
I think the Zeiss is handling very differently than what I've experienced w/ the Canon telephotos I have. Even my old Olympus 28mm w/ a lens converter so I can use it on a Canon, appears less complex then the Zeiss, but it's not as wide as the 25mm and it's widest F stop isn't nearly as wide as F2.

Again, thanks for the website. I have to go through it more because it's rather complex talk, but the different calculators are very interesting for real-life situations.
Bill

Jan 19, 2015 at 01:41 AM

mMontag
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p.2 #2 · p.2 #2 · Is it me or is it there a lens problem???

Landscape Photography 101

Know your equipment: Canon 6d - DLA - see chart in link

http://www.the-digital-picture.com/Reviews/Canon-EOS-6D-Digital-SLR-Camera-Review.aspx

http://www.the-digital-picture.com/Canon-Cameras/Diffraction-Limited-Aperture.aspx

Use tripod with decent ballhead

For DSLR - use mirror lock-up or LV

Use shutter timer or remote

Know your equipment - Old school approach - The 25/2.8 has a distance scale - you can use that directly by photo testing and review of image samples - i.e. - take photo samples using the distance scale coordinating hyperfocal distance to closest object in the scene and MFD of lens - then use focus bracketing (move your focus using the distance scale adding sample images for review) by studying the points on the distance scale and sharpness / IQ of your sample images you will learn where that lens is the sharpest for various scenes.

http://www.cambridgeincolour.com/tutorials/hyperfocal-distance.htm

Jan 19, 2015 at 11:24 AM

WhyFi
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p.2 #3 · p.2 #3 · Is it me or is it there a lens problem???

I'll echo many of the points that have already been raised but will add that any time I've seen someone compare a WA to a tele, they have done relatively little work with WA and have some unrealistic expectations.

WAs have a *much* wider FoV and, as such, are going to have a far, far fewer 'on-target' pixels at the same subject distance.

Jan 19, 2015 at 11:56 AM

billsamuels
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p.2 #4 · p.2 #4 · Is it me or is it there a lens problem???

So yesterday afternoon I took a typed page and posted it on the outside of my house, set up my Canon 6D on a tripod about 5 feet away with the Zeiss lens on it. However, I shot these pictures slightly lower than the elevation of the paper so that the page was at a 15 degree angle. This means that the bottom of the piece of paper was closer than the top of the page, hence, you can really see the depth of field between the bottom of the page and the top of the page!

I set the ISO at 400, and very carefully focused the lens on the page of print. I then went right down the range of F/stops starting at F/2.0 and shot it from F2.0 all the way up to F/22. The one point that made this interesting is that I shot the

Then I downloaded it into Lightroom and using the compare windows (2 windows), I was able to compare the F/2.0 to each F/stop thereafter. From there, I took a SCREEN PRINT of each set of pages, one page at F/2 the second at whatever F/stop I was comparing. I would Cut & Paste into WORD and then converted that entire series into a PDF.

So I'm not sure how I can show you all the series for this particular lens, but it's in a pdf and basically, from F/13 on up to F/22 the DOF for this lens is much improved!!! My shot at F2.0 is awful so now I see why the picture in the redwoods is so blurred. But both at F/11, you get a good DOF with the Zeiss 25mm ZE and by F/18 you have excellent DOF. At F/22 the DOF throughout the frame is excellent as well.

I should mention that this is why I did this at an angle, so you can see the depth of field over the entire frame, not just the center. The top of the page is at the top of the frame, and the depth of field at the top of the page is excellent even at F/22! And it's best around F/13-F/18.

I don't have cloud storage, otherwise, I'd put it there. If there is a similar place on FM, I"d put it there as well.
Bill

Edited on Jan 21, 2015 at 11:53 AM · View previous versions

Jan 21, 2015 at 12:10 AM

WhyFi
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p.2 #5 · p.2 #5 · Is it me or is it there a lens problem???

Well... yes. Stopping down improves DoF significantly when you have a short focus/subject distance, so I'm not sure what the significance of the test is.

Jan 21, 2015 at 09:08 AM

DaveOls
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p.2 #6 · p.2 #6 · Is it me or is it there a lens problem???

You mentioned a circular polariser in the first post. You're probably losing a stop or two of light. Take the polariser off and try shooting again. Unless you're using a high end filter, you're probably going to lose sharpness.

Jan 22, 2015 at 08:33 AM

sandycrane
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p.2 #7 · p.2 #7 · Is it me or is it there a lens problem???

billsamuels wrote:
So yesterday afternoon I took a typed page and posted it on the outside of my house, set up my Canon 6D on a tripod about 5 feet away with the Zeiss lens on it. However, I shot these pictures slightly lower than the elevation of the paper so that the page was at a 15 degree angle. This means that the bottom of the piece of paper was closer than the top of the page, hence, you can really see the depth of field between the bottom of the page and the top of the page!

I set the...Show more →

Gosh.
Again:
If you want to reliably judge a lens' performance you have to go by certain rules. These rules have been outlined by several people here.

The camera must be held steady. Tripod?
Shutter speed must be reasonable.
The lens must be at optimum aperture: f5.6 - f8.
The lens must be in focus. LiveView?
Sensitivity should be set at base ISO.
Your target should be planar and perpendicular to the optical path. Not too close

So far you seem to have done just about everything wrong.

Of course, you are free to do anything you want, but when you ask for our advice and then not follow it , it becomes frustrating for us. I would suggest that you find yourself a book on modern digital photography and read it.
Once you have followed the rules and have gained confidence in your camera and lens go out and have some fun.

Jan 22, 2015 at 09:47 AM

naturephoto1
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p.2 #8 · p.2 #8 · Is it me or is it there a lens problem???

Another thing comes to mind, and I don't like to be blunt about this, but you do understand that there is a big difference between sharpness and depth of field?

As several of us have indicated now, the Zeiss lens will in all livelihood be sharpest at either f5.6 or f8. The least amount of Depth of Field will be widest open which is f2 with the greatest amount of depth of field at f22. Yes you will have more depth of field as you stop the lens down to smaller apertures, but you get into a situation of lens diffraction quite possibly starting at about f11 and it becomes worse as you stop down even more. So, you have to decide depending upon the circumferences do you want the best (or at least acceptable) sharpness or greatest amount of (or acceptable) depth of field. Sometimes it makes much more sense to rethink an image and recompose so that you can obtain both.

Rich

Jan 22, 2015 at 10:51 AM

AndereObjektiv
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p.2 #9 · p.2 #9 · Is it me or is it there a lens problem???

this may help:

http://photo.blogoverflow.com/2012/06/the-realities-of-resolution/

Jan 23, 2015 at 11:04 AM

molson
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p.2 #10 · p.2 #10 · Is it me or is it there a lens problem???

sandycrane wrote:
Gosh.
Again:
If you want to reliably judge a lens' performance you have to go by certain rules. These rules have been outlined by several people here.

The camera must be held steady. Tripod?
Shutter speed must be reasonable.
The lens must be at optimum aperture: f5.6 - f8.
The lens must be in focus. LiveView?
Sensitivity should be set at base ISO.
Your target should be planar and perpendicular to the optical path. Not too close

In addition to the excellent advice above, I would add - remove the polarizing filter for testing sharpness.

The loss of light makes it harder to focus accurately, plus a cheap (or damaged) polarizer may throw the focus off.

Jan 23, 2015 at 11:56 AM

AhamB
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p.2 #11 · p.2 #11 · Is it me or is it there a lens problem???

billsamuels wrote:
I don't have cloud storage, otherwise, I'd put it there.

Get a free Dropbox account (or Google Drive, or Microsoft OneDrive, etc. etc.)?

For a simple sharpness test I'd just take some simple real-world landscape images and medium distance shots. Keep the ISO reasonably low (400 or lower) and shutter speed high enough. Don't use filters that take away light (polarizer). Use a tripod or other kind of support to rule out camera shake. Then you can take some aperture series, but between f/5.6 and f/8 you should get tack sharp results. Use live view and magnified view to make sure you get the best possible focus.

Jan 23, 2015 at 12:07 PM

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