Mark9473
Well-known member
Please also have them check for what appears to be massive spherical aberration, as per the information posted above. CA is the secondary problem at this point.
-
Welcome to BirdForum, the internet's largest birding community with thousands of members from all over the world. The forums are dedicated to wild birds, birding, binoculars and equipment and all that goes with it.
Please register for an account to take part in the discussions in the forum, post your pictures in the gallery and more.
zeiss 8/10x54 HT (1 Viewer)
- Thread starter Vespobuteo
- Start date
Please also have them check for what appears to be massive spherical aberration, as per the information posted above. CA is the secondary problem at this point.
Sagittarius
Well-known member
Rather shocking to hear of these problems with the 54mm HTs. :eek!: |:||
John Russell
Well-known member
Henry,
What a typically clear and simple demonstration!
Perhaps you got the World Cup special edition for Italian fans. It does look like their flag out at the edges.
John
What a typically clear and simple demonstration!
Perhaps you got the World Cup special edition for Italian fans. It does look like their flag out at the edges.
John
Thanks Henry for the great pictures! It really shows the large amount of CA in the 54. I assume that the 8x56 FL is your own--the CA on it is quite tolerable. You & Kimmo saved me from purchasing one of the new 8x54s--think I'll now wait & hope that the Swaro 8x56 SLC will make it to the States or consider a Europe purchase!
henry link
Well-known member
Sorry to hear that, we need more guinea pigs. It will make things interesting if someone finds a good 54HT.
I should add some caveats about the photos.
It was very difficult to center the tiny area that is free of lateral color in the HT. It's just as difficult to center it and keep it centered when you are actually looking through the binocular. I picked the photo I posted because the lateral color is nearly symmetrical along the horizontal axis, but it's a little off on the vertical axis, which causes the color fringes on the horizontal members of the central cross. For the best comparison with the FL image ignore those horizontal fringes and line up the center cross of the HT image with the first bar to the right of the cross in the FL image, which is the most color free FL bar. That gives a pretty accurate view along the horizontal axis of the difference that the eye really sees between the two.
Also remember that these are magnified images of 13º of apparent field. For my computer the image subtends about 13º when viewed from about 6' away.
Henry
I should add some caveats about the photos.
It was very difficult to center the tiny area that is free of lateral color in the HT. It's just as difficult to center it and keep it centered when you are actually looking through the binocular. I picked the photo I posted because the lateral color is nearly symmetrical along the horizontal axis, but it's a little off on the vertical axis, which causes the color fringes on the horizontal members of the central cross. For the best comparison with the FL image ignore those horizontal fringes and line up the center cross of the HT image with the first bar to the right of the cross in the FL image, which is the most color free FL bar. That gives a pretty accurate view along the horizontal axis of the difference that the eye really sees between the two.
Also remember that these are magnified images of 13º of apparent field. For my computer the image subtends about 13º when viewed from about 6' away.
Henry
Last edited:
Thanks Henry.
It appears that the color free zone of the FL is not well centered on the target, but is aimed couple of steps to the right. Not meaning to seem overly critical, but that was giving me a confused impression of the FL at first. The FL looks a lot better for sure!
Ron
It appears that the color free zone of the FL is not well centered on the target, but is aimed couple of steps to the right. Not meaning to seem overly critical, but that was giving me a confused impression of the FL at first. The FL looks a lot better for sure!
Ron
henry link
Well-known member
Ron,
To my eyes it looks like the first bar to the right is a little better than the second one. The true center is certainly somewhere between them, but I think it's closer to the first one. I'll see if I can find an FL photo with better centering. I'm afraid these backyard methods don't have the finest tolerances. I just squeeze off a lot of photos and hope a few are close enough. Happily, in this case the difference between the FL and HT is stark.
Looks like I also got my arithmetic wrong (forgot to double) and was a little too generous with the distance between the bar centers (it's about 1º instead of 1.3º), so I went back and corrected those.
Henry
To my eyes it looks like the first bar to the right is a little better than the second one. The true center is certainly somewhere between them, but I think it's closer to the first one. I'll see if I can find an FL photo with better centering. I'm afraid these backyard methods don't have the finest tolerances. I just squeeze off a lot of photos and hope a few are close enough. Happily, in this case the difference between the FL and HT is stark.
Looks like I also got my arithmetic wrong (forgot to double) and was a little too generous with the distance between the bar centers (it's about 1º instead of 1.3º), so I went back and corrected those.
Henry
binomania
Well-known member
Dear Karmantra, in the next weeks i am able to write about a comparison with these binoculars:
1) Swarovski SLC 8x56 (New)
2) Zeiss HT 8x54
3) Zeiss Conquest HD 8x56
4) Kowa BD8x56 Prominar
and others..
On 6-7 September i've organized a little meeting in Valtellina for the new Zeiss SF and the new APM 100 APO, but i think that me and the partecipants will find the time to do also this comparative.
http://www.binomania.it/wordpress/?p=6511
Please, wait
Piergiovanni
kestrel1
Well-known member
Dear Karmantra, in the next weeks i am able to write about a comparison with these binoculars:
1) Swarovski SLC 8x56 (New)
2) Zeiss HT 8x54
3) Zeiss Conquest HD 8x56
4) Kowa BD8x56 Prominar
and others..
On 6-7 September i've organized a little meeting in Valtellina for the new Zeiss SF and the new APM 100 APO, but i think that me and the partecipants will find the time to do also this comparative.
http://www.binomania.it/wordpress/?p=6511
Please, wait
Piergiovanni
Hi,
take also Nobilem 8x56 please, like in previous "King of twilight"
Like it much, quite old but still one of best /except the FOV/
Best regards Kestrel
binomania
Well-known member
Hi Kestrel, Ok, we should have also a specimen of Nobilem 8x56
Best Regards!
Piergiovanni
JabaliHunter
Well-known member
I look forward to that Piergiovanni!
Of course it would also be nice to compare the 8x56FL too, but that may be too much to ask!
Of course it would also be nice to compare the 8x56FL too, but that may be too much to ask!
Gijs van Ginkel
Well-known member
Dear all,
I had the opportunity to compare the 8x54HT with the 8x56SLC-WB at the Dutch Birdfair last weekend.
Some observations: the HT is not brighter than the SLC. That is not so strange, since the SLC has a measured light transmission of 95% at 550 nm and it has a slightly larger exit pupil.
Color dispersion was very low in the SLC and I could only see it at the very edge of the image. Color dispersion was much more in the HT and already quickly visible not far from the centre of the image.
The SLC has only a small zone of unsharpness at the edge of the image, that unsharp zone is larger in the HT.
The focussing speed of the HT is about 1,3 rotations from close focus to infinity, while it is 1,75 rotations for the SLC. Both binoculars have a good handling comfort.
I hope to test both binoculars for a longer period of time in the near future.
Gijs
I had the opportunity to compare the 8x54HT with the 8x56SLC-WB at the Dutch Birdfair last weekend.
Some observations: the HT is not brighter than the SLC. That is not so strange, since the SLC has a measured light transmission of 95% at 550 nm and it has a slightly larger exit pupil.
Color dispersion was very low in the SLC and I could only see it at the very edge of the image. Color dispersion was much more in the HT and already quickly visible not far from the centre of the image.
The SLC has only a small zone of unsharpness at the edge of the image, that unsharp zone is larger in the HT.
The focussing speed of the HT is about 1,3 rotations from close focus to infinity, while it is 1,75 rotations for the SLC. Both binoculars have a good handling comfort.
I hope to test both binoculars for a longer period of time in the near future.
Gijs
Gijs,
Thanks for sharing your observations. They closely match mine and those made by Henry. The phenomenon that you call color dispersion is what we have called lateral chromatic aberration. It is odd that it would be more prominent in the big HT than in the big Zeiss FL or the big SLC's, but that is what our observations show.
It will be interesting to hear what you find in your more extended testing.
Kimmo
Thanks for sharing your observations. They closely match mine and those made by Henry. The phenomenon that you call color dispersion is what we have called lateral chromatic aberration. It is odd that it would be more prominent in the big HT than in the big Zeiss FL or the big SLC's, but that is what our observations show.
It will be interesting to hear what you find in your more extended testing.
Kimmo
NDhunter
Experienced observer
Henry:
Your issues about the Zeiss HT 8x54 are now confirmed by Binomania.
The recent post on the site, Oct. 17th, has a comparison with the Zeiss Conquest HD 8x56 and the Swarovski SLC HD 8x56.
The HT 8x54 was lacking in sharpness, resolution, and had much more
field curvature and distortion than the others.
Jerry
james holdsworth
Consulting Biologist
Yep, it is flabbergasting for the $1000 cheaper Conquest to clearly perform at a higher level - flabbergasting and embarrassing for Zeiss.
Well past time to recall the entire 54 mm line and try again - this time aiming for a quality level a bit above that of a $100.00 Chinese knock-off. Zeiss has been talking the talk, when it comes to quality lately - let's see them walk the walk.
Thanks and no surprises there, Jerry.
^^^ in reality a community with which I am very closely associated with and in which virtually no-one has shown any interest in this product save as a curiosity to compare with the SLC.
henry link
Well-known member
Jerry,
Thanks for the heads up.
I'm not at all surprised by that review. I think anyone who carefully compares a tripod mounted 8x54 HT to a low aberration reference will have to notice that something is wrong.
I realize now that my review didn't say much about off-axis performance. It just seemed pointless for a binocular that couldn't reach a truly sharp focus in the field center. So FWIW, I found the HT distortion profile followed the traditional Zeiss pattern of applying about enough pincushion distortion to counteract angular magnification distortion, so I think most people would find panning unobjectionable. I also noted the usual Zeiss style off-axis astigmatism. The astigmatism by itself is probably similar to the 8x56 FL, but aberrations are additive, so when a larger amount of spherical aberration and lateral color are added to the astigmatism of the HT its off-axis image quality winds up looking noticeably worse than the FL.
Henry
Similar threads
