Parariss wrote:
So, all together it's Bigfoot, the Loch Ness Monster, and "a good copy of the CV 15/4.5?"
A good copy might be hard to get, though there is some evidence they are a bit better on average now, but I doubt if a bad copy would be improved by a front filter...
Fred Miranda wrote:
It will work fine with TAP. (But I'm not 100% sure if TAP will allow focus at infinity distance)
I should be able to test both ZM 28/2,8 and ZM 35/1.4 with their respective filters on Jan 10th.
Fred
Despite having ordered like a week ago just today I got an expected delivery date which is... February 10th
Thank you for the feedback. The CV15 III is an exceptional lens that I never travel without. I sold the original version for the III in M mount with TAP after upgrading to the A7R2 and have been very happy with it. On my copy, only the extreme edges and corners have a small amount of softness which is only noticeable on distant objects when pixel peeping. Closer objects are sharp from corner to corner. Probably not worth the effort to try to correct with a PCX lens.
Fred Miranda wrote:
That's bad news. I will check with my contact and see if I'm still on for Jan 10th delivery.
Thanks to Haruhiko I found a second supplier, but for a coated version delivery time is also 5 weeks.
I ordered an uncoated one which is in stock and will be devilevered shortly, so I was told.
Will have to do until February
BastianK wrote:
Thanks to Haruhiko I found a second supplier, but for a coated version delivery time is also 5 weeks.
I ordered an uncoated one which is in stock and will be devilevered shortly, so I was told.
Will have to do until February
It thought the SLB-50-5000PM was multi-coated and was not aware there was a uncoated version as well.
Fred Miranda wrote:
It thought the SLB-50-5000PM was multi-coated and was not aware there was a uncoated version as well.
You are partly correct, the SLB-50-5000P (without "M" at the end) is the uncoated version from Opto Sigma.
But I (in addition to my "will-be-delivered-in-february SLB-50-5000PM") ordered a similar lens from the manufacturer Eksma Optics.
BastianK wrote:
You are partly correct, the SLB-50-5000P (without "M" at the end) is the uncoated version from Opto Sigma.
But I (in addition to my "will-be-delivered-in-february SLB-50-5000PM") ordered a similar lens from the manufacturer Eksma Optics.
Yes, that's right. When there is an ‘M’ at the end of the part number, it is calling out a visible AR coating.
The M version will be AR coated on both sides Rave<0.6% @ 400-700nm
Not sure I would label extreme field curvature myself more like moderate. CV 35 1.7 has more for instance. Sigma Art 35 1.4 has a lot also . If we can get F6.3 with the ZM than not sure I would put it at extreme . The CV 35 1.7 needs F9. The 50 sonnar 1.5 not sure it gets there even at F11.
Be interesting to see if this did work on the CV though
Without any front-end filter on a stock A7RII, the ZM 28/2.8 is acceptable at f/10 across the field (infinity)
The extreme edges are good but not great at this aperture. I am hoping that adding a 1.5 PCX filter will improve this performance.
Here are some crops without the front-end filter. (I will only receive the filter on Jan 10th for a comparison)
Fred Miranda wrote:
Without any front-end filter on a stock A7RII, the ZM 28/2.8 is acceptable at f/10 across the field (infinity)
The extreme edges are good but not great at this aperture. I am hoping that adding a 1.5 PCX filter will improve this performance.
Here are some crops without the front-end filter. (I will only receive the filter on Jan 10th for a comparison)
Interesting!
I started by comparing the 28mm ZM MTF with the Loxia 2/35 to get a sense of how they compare, and whether if the 28 ZM can be got to near native performance on the Sony with the aid of front end filters, it would be competitive.
So the published MTFs have the ZM 28 not quite a s good as the Loxia 35; actually notably worse in the midfield, similar in the centre and corners, where there is a quite bit of (probable) astigmatism in both.
But then I thought I should have a look at the ZM 2/35 biogon on which the Lox is based. VERY interesting. The Loxia, as we have seen, is much better than the 2/35 when used on a Sony. But the 2/35 ZM Biogon has a noticeably nicer MTF than the Loxia (assuming their intended cover glasses, obviously). So whatever tweaks were done to the Biogon to turn it into a Loxia Biogon still leave some unresolved astigmatism (that the ZM doesn't really have). The ZM 2/35 is way ahead of the ZM 2.8/28
This makes me a little pessimistic about a front filter on the 28; that solution (especially since it'll be a stock filter and not one calculated to purpose) may improve it's performance on Sony quite a bit, but it seems reasonably to assume that it won't provide nearly the improvement that the recalculations that made the Loxia provided — which as we have seen are only partial. In which case we can expect that a front filter corrected ZM28 will be at least as bad, and probably more, relative to a native 2.8/28 ZM as the Loxia is to the native ZM35
If all that's the case (many assumptions, I know) then I doubt if a corrected 2.8/28 ZM would be really desirable. The lens is starting off worse than the Loxia native - for -native, and it's even corrected on Sony it will be even worse still than the Loxia.
Of course this might all be wrong: I look forward to tests. Also even if I'm right, the correction might make a lot of sense for someone who already owns one.
I started by comparing the 28mm ZM MTF with the Loxia 2/35 to get a sense of how they compare, and whether if the 28 ZM can be got to near native performance on the Sony with the aid of front end filters, it would be competitive.
So the published MTFs have the ZM 28 not quite a s good as the Loxia 35; actually notably worse in the midfield, similar in the centre and corners, where there is a quite bit of (probable) astigmatism in both.
But then I thought I should have a look at the ZM 2/35 biogon on which the Lox is based. VERY interesting. The Loxia, as we have seen, is much better than the 2/35 when used on a Sony. But the 2/35 ZM Biogon has a noticeably nicer MTF than the Loxia (assuming their intended cover glasses, obviously). So whatever tweaks were done to the Biogon to turn it into a Loxia Biogon still leave some unresolved astigmatism (that the ZM doesn't really have). The ZM 2/35 is way ahead of the ZM 2.8/28
This makes me a little pessimistic about a front filter on the 28; that solution (especially since it'll be a stock filter and not one calculated to purpose) may improve it's performance on Sony quite a bit, but it seems reasonably to assume that it won't provide nearly the improvement that the recalculations that made the Loxia provided — which as we have seen are only partial. In which case we can expect that a front filter corrected ZM28 will be at least as bad, and probably more, relative to a native 2.8/28 ZM as the Loxia is to the native ZM35
If all that's the case (many assumptions, I know) then I doubt if a corrected 2.8/28 ZM would be really desirable. The lens is starting off worse than the Loxia native - for -native, and it's even corrected on Sony it will be even worse still than the Loxia.
Of course this might all be wrong: I look forward to tests. Also even if I'm right, the correction might make a lot of sense for someone who already owns one....Show more →
Makes sense David. Still, I'm stubborn and want to see real world tests with these filters.
I will throw in the Zeiss 28/2 ZF into the mix when comparing the ZM with filter and no filter.
There is no perfect 28mm prime for the A7RII and any solution has to blow away what I get with my 16-35/4@ 28mm, which is flat-field and actually very good at f/6.3 across the field. I'm hoping the ZM 28/2.8 will be at least a little better with more micro-contrast for a very small 28mm prime alternative.
Zeiss 28/2 ZF vs Zeiss 28/2.8 ZM (Best case scenario)
Leica 28/2.8 Elmarit-R - This lens seems to be perform great on the A7RII. I just added here for comparison. I don't think the ZM is far behind when used on the correct filter stack.
I'll take the logical approach here so if it's good at F10 without filter and we want to try for F8 which is a 1.5 stop improvement. Now do we think we could get 1.5 stop improvement factor with filter on it. It looks like at least the ZM 35 gets at least a stop with its filter. So maybe it's possible. Just thinking out loud 😇
GMPhotography wrote:
I'll take the logical approach here so if it's good at F10 without filter and we want to try for F8 which is a 1.5 stop improvement. Now do we think we could get 1.5 stop improvement factor with filter on it. It looks like at least the ZM 35 gets at least a stop with its filter. So maybe it's possible. Just thinking out loud 😇
I'm hoping the ZM 35/1.4 will be optimal at f/4 and the ZM 28/2.8 at f/5.6 (with their respective filters)
Dec 23, 2016 at 07:39 PM
Steve Spencer Offline • • • • • • • Upload & Sell: On
Fred Miranda wrote:
I'm hoping the ZM 35/1.4 will be optimal at f/4 and the ZM 28/2.8 at f/5.6 (with their respective filters)
I think that is a lot to expect. I think a more reasonable expectation is the ZM 35 f/1.4 will be optimal at f/5.6 and the ZM 28 f/2.8 will be as good at f/8 as it is in your samples at f/10, which I don't really see as optimal. For me I would settle for the filters just primarily working in closer in shooting, say 10m or less and getting performance in these close shots that rivals the lens on a Leica M240. Now that looks totally possible and that combined with good performance from f/5.6 or even f/6.3 as it is now leaves it as a much stronger lens.
Love to be wrong , just not sure we can push it that far. I wonder if their is a 28 that is a little better today maybe like the CV 28 Ultron for instance that we can gain a lot with a filter. Still can use the TAP
Dec 23, 2016 at 08:34 PM
Steve Spencer Offline • • • • • • • Upload & Sell: On
GMPhotography wrote:
Love to be wrong , just not sure we can push it that far. I wonder if their is a 28 that is a little better today maybe like the CV 28 Ultron for instance that we can gain a lot with a filter. Still can use the TAP
I think the best bet for a small lens might be the Leica M 28 elmarit that has been redesigned for digital. That lens like the ZM 35 f/1.4 already is pretty good without a front end filter as Fred's tests showed earlier. That lens also has 10 aperture blades so it ought to have nice sunstars that rival the ZM and Loxia lenses.
I also think that the 28 lux ASPH is even better and in my tests looks awfully good from about f/4 without any filter, but that lens is in a whole different price category. If I remember rightly the Leica M 28 cron did not do quite as well without a front end filter in Fred's tests, so the one to think about may be the new M 28 elmarit.
