Try this first...
When you see the disappointing image, dis-engage and then re-engage the IS. Did the image change? Do this a few times and report what you see.
Posted 18 July 2018 - 12:40 PM
Try this first...
When you see the disappointing image, dis-engage and then re-engage the IS. Did the image change? Do this a few times and report what you see.
Posted 18 July 2018 - 07:36 PM
I should have mentioned that this has nothing to do with the IS, which works perfectly well thank you very much
I get the same result mounted on a tripod with IS off. Bright stars are not well resolved. The brighter the star the more bloated they appear.
It doesn't bother me that much - but it does make me wonder whether something isn't perfect with this particular set of 18x50's which could affect other aspects as well. If that were the case then I could send them back for a refund and purchase another set (which may or may not be better). I have a few days to make that decision (30 day refund policy).
Doing a bit of reading it seems like what I'm seeing could be spherical aberration. This from EdZ "If the stars seem never to focus to a fine point, but at best remain slightly bloated and are still circular, and it cannot be focused out it is probably spherical aberration." I'm only seeing this on moderately bright stars though. Fainter stars are resolving nicely, like in the 10x30's.
At this point I'm inclined to think that what I'm seeing is "par for the course" with the 18x50's and hang onto this pair. But I am curious about others experience observing bright stars with them. If it is a general thing that everyone sees (i.e. bloating of bright stars) then I can live with it. I'd just hate to think I have a poor sample and didn't return it.
I gotta say though, overall these Canon 18x50's are pretty great.
Nick.
Edited by Nick-Sydney, 18 July 2018 - 11:14 PM.
Posted 19 July 2018 - 02:30 AM
Hi there
I tried some days ago my 18x50's (mounted on a tripod - stabilization OFF) to read a distant small parking note, the sharpness level was incredibly high (very easy to read everything perfectly clear) very easy to find "the right focus point".
But once hand held (stabilization on) no matter how times I did it (turned on and off) or had waited for the stabilization system get "stable" after engaging it, the sharpness level was visibly affected and starting to floats...sometimes I could see at the same way very (fine details as when off and tripod mounted), but the sharpness level will not remain "stand still" starting to blur as if heat waves were coming from the ground.
I have got some days ago a Nikon 14x40 and I tried then both (hand held, stabilization engaged) to watch again the same parking sign and then some stars.
Despite the not "so good" Nikon's apparent field of view as the 18x50's , the sharpness level (stabilization on) through these was better and consistent.
I could read clearly the same sign, I mean clear just because the image sharpness was not floating (losing sharpness/becoming sharp again) as through the 18x50's.
The bright stars looked tighter (without any spikes or signs of astigmatism) through the Nikon and when pushing it out of focus (intra or extra focus) the star's shape changed coming from a perfect "point like" till becoming a disc like, while through the 18x50's even "hunting for a right focus point" I couldn't achieve the same "tight star shape", and using a bright star as a test (through the Canon) when doing the same (intra extra) the star changed it shape from a more or less "bloated point" to an oval shape before becoming a disc.
I could see a big diference (mainly) when watching for a very small (not so bright) double star: while through the Nikon it was clearly sharp and "easy to see" as 2 tight very small stars, through the Canon despite of course being clearly obvious being "a double star" it was more as a bloated vision, sometimes becoming just as one bloated star before again showing it separation.
The Nikon 14x40 isn't perfect however, it stabilization despite being huge against the one in the Canons it show a kind of very residual "micro-shaking" sometimes, not enough to spoil fine details and the sharpness doesn't floats, but you can notice it there. For me its better however this way (Nikon 14x40) than the 18x50's regarding a better and really consistent sharpness level when stabilization is engaged.
Pedro
Edited by pedro, 19 July 2018 - 07:14 PM.
Posted 19 July 2018 - 07:16 AM
Interesting comparisons between the 14x40's and 18x50's.
Stars remain round both in and out of focus in my 18x50's so I don't think it's astigmatism. Which is why I'm wondering if it might be spherical aberration.
I'm using lithium batteries and the IS is working well. If I aim near zenith then I can't hold the binos very still and the IS struggles to compensate, which is to be expected. I try and lean against something or rest my elbows on a railing while seated. Freestanding is much more tiring and I can only hold them steady for 5 minutes or so before needing a rest. But with a bit of support the IS works well. I haven't tried any non-lithium batteries and I'm not planning to at this stage. The 10x30's haven't been getting much attention lately.
Edited by Nick-Sydney, 19 July 2018 - 07:17 AM.
Posted 19 July 2018 - 08:26 AM
Hey Nick,
I have both the 10x42L and 18x50. Judging by what you say, I don't think you have a dud.
I too find that on the brightest stars (Sirius, Alpha Cen) and the planets they can produce are all sorts of funny artefacts.
The 18s actually have CA. They are harder to hold steady and are more sensitive to any setting not being quite right. For example If the IPD is not set right or if the diopter difference between the eyepieces is out just a little bit, it shows up on the brightest stars and the visible planets.
But it pulls in more DSOs, more lunar detail, easier to identify birds and planes. Just more of everything so I now use itt 80% of my observing. As you already have the 10x30, I'm not sure that 15x is a big enough jump to warrant getting a second pair. But at 18x, yes definitely it brings a substantially different view.
I still think the 10s give a more beautiful view, but the 18s pull in more information.
Good luck either way.
cheers
Adam
Posted 20 July 2018 - 02:21 AM
Thanks Adam. This is exactly what I wanted to know. I've noticed a bit of CA on the moon and Joop but wasn't thinking of that causing the bloated stars. In any case it seems that my pair are ok, which I thought they were, but when you're spending that much money you don't want to be wondering.
Glad also for the reinforcement of going 18x over 15x. I was thinking that 15x probably wasn't a big enough jump - but I did agonize over the decision because I saw a really good deal on the 15's and had to pay a lot more for the 18's. For the moon you definitely want everything you can get. The jump to 18x is substantial for sure.
I live right under a flight path. Tracking planes from relatively close range is a little tricky. By the time I see them I don't have a lot of time to get them in view and have to mess with focus. I think the 15's might be slightly better from that point of view for me - but that's not a primary concern. I'm looking forward to an ISS pass.
I'll play around a bit more with the IPD as well to see if I can eek out any improvement. I've been hoping I might be able to catch a couple of bands on Joop, but nothing so far.
Thanks again for the info.
Nick.
Edited by Nick-Sydney, 20 July 2018 - 02:57 AM.
Posted 21 July 2018 - 06:00 PM
Hey Nick,
Something that is really compelling for keeping the 18x50 : The Large Magellanic Cloud. If I were still living in Sydney I'd probably head to Jervis Bay or somewhere like that. For me the 18x50 strike just the right balance between magnification and FOV to really appreciate this fascinating object. I drove northwest of Brissie in the wee hours of the morning to catch Andromeda, so not ideal when turning South but oh my... breathtaking doesn't do it justice.
Posted 24 July 2018 - 05:48 AM
Thanks for the tip Adam.
I'm looking forward to getting to a dark location and checking out the LMC and SMC with them. It's definitely on my todo list; as is Andromeda.
Jervis Bay is a nice option. A friend of mine was down there last week (wished I could have been there with him). Even in Sydney I've been getting some "ok" views of milk and dark lanes. The magnification obviously helps, as does the IS.
I just ordered a set of Visionking 5x25's. Hoping they'll make a nice complement to the Canon 10x30 and 18x50 when I get out there. Not sure when I'll get down to Jervis but I'm definitely going to have to go for a drive...
Edited by Nick-Sydney, 24 July 2018 - 05:50 AM.
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