p.6 #1 · FM Lens test for Centering (Mount tilt / swing)
@fred miranda why clock/anti clockwise and upside down movements. Why not focus at the centre and just move the camera to bring the subject at each corner?
I focussed at the centre. Now when i tilt my camera clock/anti-clock wise and upside down etc...the subject still remains in the centre. Its like i am revolving the camera around a subject.
To put subject in the corner i will have to move the camera position.
??
p.6 #2 · FM Lens test for Centering (Mount tilt / swing)
So i anyway did the test on my 17-28 as per instructions. Focussed in the center and then took 4 pictures of corners without tilting etc cause the subject was too far to make any difference from camera movement. It was not the similar framing as it would have been had i did tilting and upside down movement of the camera but it gave me a fair idea. My lens seems to be ok at 17, 24 and 28.
p.6 #6 · FM Lens test for Centering (Mount tilt / swing)
Thank you.
The right side on other photos seems to have more chromatic aberration (I think) and is a bit more smeared, though that's at 1.8 so should bring my expectations down, I guess!
Not sure if this is chromatic aberration or just slight smearing of edges on the right?
p.6 #7 · FM Lens test for Centering (Mount tilt / swing)
rainio wrote:
Thank you.
The right side on other photos seems to have more chromatic aberration (I think) and is a bit more smeared, though that's at 1.8 so should bring my expectations down, I guess!
Not sure if this is chromatic aberration or just slight smearing of edges on the right?
eg.
I often take a set stopped down 1-2 stops to eliminate the effects of CA.
p.6 #11 · FM Lens test for Centering (Mount tilt / swing)
DaveFP wrote:
I don't understand the value of turning the camera upside-down.
Anyone know?
I believe from what Fred and others have said in this thread that it helps to compare by having the images in the same orientation and maybe more importantly it keeps the images at the same relative focus plane if focused at infinity (which is what is recommended).
My deal is I can't manual focus worth beans apart from the Loxia and CV lineup. So I use auto focus but I have decoupled the shutter and focus (I use back button focus) so focus isn't changing once I focus on the subject in the center. I 'think' that's okay for this test.
p.6 #12 · FM Lens test for Centering (Mount tilt / swing)
gunmetal wrote:
I believe from what Fred and others have said in this thread that it helps to compare by having the images in the same orientation and maybe more importantly it keeps the images at the same relative focus plane if focused at infinity (which is what is recommended).
My deal is I can't manual focus worth beans apart from the Loxia and CV lineup. So I use auto focus but I have decoupled the shutter and focus (I use back button focus) so focus isn't changing once I focus on the subject in the center. I 'think' that's okay for this test....Show more →
Would that really matter if the subject is at infinity?
Seems like there would be no discernable difference when upside down but I don't really know.
I simply shoot all corners rightside up.
Seem to work OK; even when the subject has fine details.
p.6 #13 · FM Lens test for Centering (Mount tilt / swing)
DaveFP wrote:
Would that really matter if the subject is at infinity?
Seems like there would be no discernable difference when upside down but I don't really know.
I simply shoot all corners rightside up.
Seem to work OK; even when the subject has fine details.
You may be right. I think the Gletscherbrunch (corner shots all right side up) method does a good job too, as long as the object is a good ways away. And for me it's a little easier to pull off without the risk of false positives.
p.6 #14 · FM Lens test for Centering (Mount tilt / swing)
rainio wrote:
Thanks.
I was thinking of trying some astro - would you keep this lens for that purpose?
Thanks for your advice.
I would run the test at 2.0, 2.2, 2.5, and 2.8 and see how your corners look. All of those apertures are fast enough for Astro. Please share. I'm interested to see how that lens looks stopped down a bit.
p.6 #15 · FM Lens test for Centering (Mount tilt / swing)
DaveFP wrote:
Would that really matter if the subject is at infinity?
Seems like there would be no discernable difference when upside down but I don't really know.
I simply shoot all corners rightside up.
Seem to work OK; even when the subject has fine details.
Hi Dave,
Tilting the camera is optional but I find it easier to see detail at the very edge of the frame and also to better compare crops side by side:
p.6 #16 · FM Lens test for Centering (Mount tilt / swing)
Fred Miranda wrote:
Hi Dave,
Tilting the camera is optional but I find it easier to see detail at the very edge of the frame and also to better compare crops side by side:
Thanks Fred.
I can see how that makes the comparison much easier.
Unfortunately I am in a congested area of NY so I don't have the required vista nearby.
I will shoot something with fine details such as a chimney with cell transmitters on it.
I try and get the subject equidistant to the corner in all four shots.
p.6 #17 · FM Lens test for Centering (Mount tilt / swing)
Fred Miranda wrote:
Hi Dave,
Tilting the camera is optional but I find it easier to see detail at the very edge of the frame and also to better compare crops side by side:
Fred how do you crop them so perfectly and combine them into one image? The directions say to zoom to 1:1, but in LR I'm not aware of a way to crop to 1:1 apart from simply "eyeballing" it.
p.6 #19 · FM Lens test for Centering (Mount tilt / swing)
Maknof wrote:
I have both bad or better lens, and for Loxia 25 it is in bad side or in good side ?
Lens is at infinity stop.
At first glance i wouldn't be too happy about an expensive prime performing like that. A second look tells me the exposure difference between the images is close to two full stops and it make it harder to judge. But, to me it seems as left side is better, you may have some swing or a slightly decentered element.
Frustrating, I know.
I would try again: increase the shooting distance somewhat, use a tripod, set the focusing and exposure both to manual, focus carefully at the center and take an image. Then set the exposure to plus one to compensate for vignetting when shooting the corner images, don't change anything but where you aim and take the corner images. That might help with the evaluating.
p.6 #20 · FM Lens test for Centering (Mount tilt / swing)
Maknof wrote:
Sorry if i resume this old thread, but it was helpful.
I have both bad or better lens, and for Loxia 25 it is in bad side or in good side ?
Lens is at infinity stop.
It looks like you used shutter speed priority and therefore the exposures are not equal.
I would advice shooting in manual exposure and make sure I turn IBIS 'off'.
