Jorge,
I don't know if you read the whole thread but my 50MP is not a dud and is very sharp across the frame except at apertures wider than f5.6 where the extreme corners get blurry.
This is something you would not even see if you are taking landscape shots with aperture f5.6 or narrower (which is usually done to get enough DOF) and when the extreme corners contain parts of the sky or not important foreground parts. The two extreme right corners of your pano are blurry and maybe this extreme corner problem we are talking about is the cause or maybe those are parts not in the DOF.
My contax N 50/1.4 is sharp too but has an infinity focus problem when shooting at apertures f2.8 (a little bit at f4) and wider.
I have all sorts of shots with the 50 f2. Is there a particular type of example you would like to see? Now you have my curious and going through some of my old shots
wayne seltzer wrote:
Yes, just confirmed today that my contax N 50/1.4 doesn't reach infinity focusing at f4 and wider. The reason probably that the corners did better is because of field curvature bringing them back into the DOF.
Here is a shot with only the same processing (only exposure adjustment and same input sharpening at closer than infinity distance at f1.4.
Can anybody with a contax N 50/1.4 tell me if their copy can reach infinity focusing wide open or not?
Wayne, I think if you have firmware greater than 3.0 (going by memory) on the Conurus lens, you can microadjust that lens for three distances to shape the focus curve (ie. at minimum focus distance, some mid distance target, and at infinity.) I think it is worthwhile to do all three. The instructions on the site are not perfectly clear, but it works. No other lens is able to this to my knowledge, only the Conurus conversions. I suspect Canon does this at their service centers, and probably for each zoom focal length as well, which is why their consumer microadjust system, while nice, is limited in its utility compared to factory settings.
If you adjust only one or two of the distances, it affects the unadjusted ones as well, as it shifts the curve (maybe a straight line, maybe a curve, I don't know, but if you use three points, it is more likely a curve than a straight line.)
I have all sorts of shots with the 50 f2. Is there a particular type of example you would like to see? Now you have my curious and going through some of my old shots
Do you have any pictures of a flat object at f4 and f5.6? Are the extreme corners sharp on these pictures?
BTW I have returned my 50MP and ordered another one, hoping to get a better corner performance. If I get the same result, I will change to the 35ZE.
erichard wrote:
Wayne, I think if you have firmware greater than 3.0 (going by memory) on the Conurus lens, you can microadjust that lens for three distances to shape the focus curve (ie. at minimum focus distance, some mid distance target, and at infinity.) I think it is worthwhile to do all three. The instructions on the site are not perfectly clear, but it works. No other lens is able to this to my knowledge, only the Conurus conversions. I suspect Canon does this at their service centers, and probably for each zoom focal length as well, which is why their consumer microadjust system, while nice, is limited in its utility compared to factory settings.
If you adjust only one or two of the distances, it affects the unadjusted ones as well, as it shifts the curve (maybe a straight line, maybe a curve, I don't know, but if you use three points, it is more likely a curve than a straight line.)...Show more →
Erichard,
Thanks, but the adjustment you talk about is for AF adjustment which I have done to now get accurate AF even at f1.4 but it can not help this case where the lens, even with manual focusing, can not achieve proper focus at f2.8 or wider on a subject at infinite distance, even if you turn it past infinity mark.
It's as if the mount is too thick.
If it's still under warranty with Conurus, they should get that straight, as this is what they are providing in particular, the EF mount. I'm surprised it made it out of Vancouver that way.
I had a look at the exif of some of your 50N pics, it says all have been focused at a distance of 5.86m, which could be correct on the Tong image but certainly not on the church images. Maybe you have to remove that tape you put there 2 months ago ;-)
At least before sending it away I would ask Conurus if they can say something about it. Just looking at their site may tell you something
I have all sorts of shots with the 50 f2. Is there a particular type of example you would like to see? Now you have my curious and going through some of my old shots
Jorge,
Like Boris mentioned, if you have a shot of a side of a building where the extreme corners of the shot are still on the side of the building and you take the shot at f4 or f2.8 or f2, check the extreme corner to see if its blurry.
Boris, I don't think your new copy will be any different as the MTF shows this extreme corner behavior. But good luck.
Andi Dietrich wrote:
I had a look at the exif of some of your 50N pics, it says all have been focused at a distance of 5.86m, which could be correct on the Tong image but certainly not on the church images. Maybe you have to remove that tape you put there 2 months ago ;-)
At least before sending it away I would ask Conurus if they can say something about it. Just looking at their site may tell you something
erichard wrote:
If it's still under warranty with Conurus, they should get that straight, as this is what they are providing in particular, the EF mount. I'm surprised it made it out of Vancouver that way.
I jus posted this problem on Conurus website, so see what he has to say.
Its not a big problem since I rarely shoot a distant landscape or subject at f2.8 or wider.
Usually, I am shooting closer than infinity when shooting wide open.
But would be nice if there is an easy fix to the problem.
Hopefully, Lotusm50 will unpack his copy of the lens soon so he can tell me if his copy doesn't have this problem.
wayne seltzer wrote:
What utility are you using to view the distance info in the exif?
I use website for EXIF: http://regex.info/exif.cgi . I have also created Javascript bookmark (this website has instructions for that), which sends automatically the image to this website, image has to be opened so that's it's directly on browser window, not on webpage. This works from my desktop, personal laptop and work laptop even all have different operating systems.
For example your Tong Dumpling Pot the summary says (there are few pages below that details):
Got this info from my Contax N 50/1.4 test shot at f2:
Basic Image Information
Camera: Canon EOS-1Ds Mark III
Lens: 50mm f/1.4
Exposure: Auto exposure, Aperture-priority AE, 1/640 sec, f/2, ISO 200
Flash: none
Focus: At 4294967295m, with a depth of field from about 312m to infinity
Date: December 29, 2009 2:23:47PM (timezone not specified)
(1 month, 15 days, 8 hours, 52 minutes, 17 seconds ago, assuming an image timezone of US Pacific)
File: 660 × 435 JPEG
184,966 bytes (0.18 megabytes) Image compression: 79%
Color Encoding:
WARNING: Embedded color profile: “ProPhoto/ROMM”
All Windows web browsers (except Safari) and many Mac web browsers ignore an embedded color profile, meaning users of those browsers will see the wrong colors for this image.
Images for the web are most widly viewable when in the sRGB color space and with an embedded color profile. See my Introduction to Digital-Image Color Spaces for more information.
wayne seltzer wrote:
Hopefully, Lotusm50 will unpack his copy of the lens soon so he can tell me if his copy doesn't have this problem.
Well, we're packing the moving truck today, and I start driving across the country mid-day Monday. Might get a chance on Monday night, if not then, Wednesday night the earliest, after I arrive at my destination. This is one of the lenses I am not entrusting to the moving truck.
Not looking forward to the 1865 mile drive. I expect to drive into a snowstorm on Monday.
Lotusm50 wrote:
Well, we're packing the moving truck today, and I start driving across the country mid-day Monday. Might get a chance on Monday night, if not then, Wednesday night the earliest, after I arrive at my destination. This is one of the lenses I am not entrusting to the moving truck.
Not looking forward to the 1865 mile drive. I expect to drive into a snowstorm on Monday.
So you will have some of your camera gear handy to take a lot of shots on your cross America journey? Have a safe trip and good luck with the weather/snowstorm.
You have to stop down the 50MP to at least f/8.0 to reach the wide open corner performance of the 35-70 or the 100MP.
I wanted to know, if this has something to do with field curvature of the 50MP. So I did another test, were I focused with 10x live view on the lower right corner:
As you can see, there is a slight effect of field curvature. But even with focussing on the corner, you have to stop down to at least f/5.6 to reach good corner performance.
Since the the 50 MP is in all other aspects a really great lens, I will keep it and will use it mainly at f/8 or f/11 for landscape shots. Center performance, contrast and bokeh of this lens is very good, even wide open.
Boris,
Judging by your original FF image, these crops represent the last 20% of the frame heading into the extreme corner? Thus the gradation of sharpness represent softness in the last 10% of the extreme corner. This is a pretty small fraction of the frame, as even the edge of the frame horizontal to the center should be pretty decent.
What if you used the Zeiss Distagon 35 f/2 and cropped to get a comparable fov?
Mike K
Mike K wrote:
Boris,
Judging by your original FF image, these crops represent the last 20% of the frame heading into the extreme corner? Thus the gradation of sharpness represent softness in the last 10% of the extreme corner. This is a pretty small fraction of the frame, as even the edge of the frame horizontal to the center should be pretty
Yes, quite small fraction of the frame. This is much ado about very, very little, IMHO. This is the least seen, least used, and often cropped 1% (or less) of the frame. As mentioned before, nearly ALL 50mm standard lens exhibit this, why this particular 50mm should be called to task for it is mind boggling.
Comparing it to a 100mm lens is useless. If you need a 100mm lens use a 100mm lens, if you need a 50mm use a 50mm. The 50mm MP is incomparable across 99% of the frame and merely comparable to all other 50mm's over the last tiny fragment of the frame. To dismiss the lens for this is a kin to throwing the baby out with the bath water. Even if the 35-70 might be a touch better in the absolute corner than the 50 MP, the performance of the 50 MP over 99+% of the frame totally and obviously dominates the old zoom. Would you really prefer to use the 35-70 over the 50MP?! I still don't get the point of all this. It's not perfect? No lens is. That is to be expected. So far we've seen nothing that isn't shown in the published MTF's. IMHO, you spent a lot of time and effort obsessing over this for very little insight or gain. If you don't want to use it because of this, that is your prerogative, but you would be leaving a lot of performance on the table that you can't get in another 50mm lens -- performance in areas of the frame that matter a great deal more than the often-unseen absolute corner. Use the lens for real photographs rather that brick walls and fences and it will never fail to impress.
wayne seltzer wrote:
So you will have some of your camera gear handy to take a lot of shots on your cross America journey? Have a safe trip and good luck with the weather/snowstorm.
Trip was delayed a few more days, but I finally made it and got settled enough to pull out the N50 and take a couple test shots with the lens wide open and focused to infinity. My N50 clearly does focus to infinity. (I should note that a quick micro-adjust of the AF on this lens was done a short while ago). In the following (unsharpened) crop, the 5D locked focus onto the mountain in the distance. It's a little soft, as we might expect from the lens wide open, but it is in focus. By the way, never even took the camera out during the drive. I was too focused on driving and getting where I was going, quickly. http://www.arcxeon.com/gallery/N50-crop-at-f14.jpg
