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Archive 2013 · Is there something wrong with this Lux 50 ASPH?

  
 
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p.2 #1 · p.2 #1 · Is there something wrong with this Lux 50 ASPH?


Hi Ron, first thank you -- your efforts have been so amazingly helpful.

One quick question -- is your adapter stopping hard at infinity, in focus? (Mine seems to focus past infinity.)

How do you take the suggestion that if the Lux ASPH isn't hitting infinity at infinity, then that will impact focus performance in general?



Nov 04, 2013 at 01:03 PM
rscheffler
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p.2 #2 · p.2 #2 · Is there something wrong with this Lux 50 ASPH?


With the adapter (Novoflex), all of my rangefinder lenses focus past infinity.

My gut feeling is that while there might be some impact on image performance of floating element lenses, I don't believe it will be significant in real world use.



Nov 04, 2013 at 01:53 PM
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p.2 #3 · p.2 #3 · Is there something wrong with this Lux 50 ASPH?


rscheffler wrote:
With the adapter (Novoflex), all of my rangefinder lenses focus past infinity.

My gut feeling is that while there might be some impact on image performance of floating element lenses, I don't believe it will be significant in real world use.


This question seems to be somewhat contentious, for example see Jonas' comment here:

https://www.fredmiranda.com/forum/topic/1251603/0#11908127

But then other people suggest there should be little-to-no difference. So it's a bit perplexing.

That said -- IF correct infinity focus really can impact overall focus performance (at least for some lens designs) AND given that your adapter is focusing past infinity THEN it's possible this could have potentially impacted the test?

I don't mean to sound as if I'm questioning your methodology -- I'm very grateful for it -- but from my recent crash course, it seems this is one detail potentially worth exploration.

-Scott



Nov 04, 2013 at 02:05 PM
rscheffler
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p.2 #4 · p.2 #4 · Is there something wrong with this Lux 50 ASPH?


My 50 Lux ASPH results on the a7 don't seem to differ greatly from what I'm used to getting from it on the M9.

I've skimmed through the discussion on whether or not it will affect image quality of floating element lenses in the other thread. I wouldn't be surprised if there is some visible difference, particularly at closer distances with subject matter requiring a flat plane of focus for optimal results. Not so sure about infinity. Someone will have to do a rigorously controlled test with an adapter that is properly shimmed for infinity vs. one that isn't. Even then, it will be interesting to see if image quality loss will be significant. Or at least as significant as that from non-optimized sensor toppings.

The characteristic of the blur you see at the edges of your NEX-7 samples seems to be that of astigmatism, and that seems to be the character of the quality drop in the mid zone area of the lens (and many other Leica lenses). But I suspect it could also be compounded by astigmatism induced by the sensor toppings. This impression is in part reinforced by Reichmann's results in the earlier link.



Nov 04, 2013 at 04:54 PM
sebboh
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p.2 #5 · p.2 #5 · Is there something wrong with this Lux 50 ASPH?


rscheffler wrote:
My 50 Lux ASPH results on the a7 don't seem to differ greatly from what I'm used to getting from it on the M9.

I've skimmed through the discussion on whether or not it will affect image quality of floating element lenses in the other thread. I wouldn't be surprised if there is some visible difference, particularly at closer distances with subject matter requiring a flat plane of focus for optimal results. Not so sure about infinity. Someone will have to do a rigorously controlled test with an adapter that is properly shimmed for infinity vs. one that isn't. Even then,
...Show more

is there any chance you could post a full sized image from the m9 + lux similar to your foliage shot on the a7 (doesn't have to be too similar, just the basic idea)? this question seems to be coming up a lot...




Nov 04, 2013 at 04:58 PM
JonPB
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p.2 #6 · p.2 #6 · Is there something wrong with this Lux 50 ASPH?


I don't have any experience with Leica M lenses--I'm an R guy--but the NEX-7 theoretically resolves 125 lp/mm. The MTF charts go to 40 lp/mm. Seeing as how the resolution drops more than double from 20 lp/mm to 40 lp/mm at 10-12mm from center, compared to peak resolution, I'd expect to see even more significant drops as the lp/mm count approaches 125.

Sure, the left side seems less sharp than the right, but even shimming with the thinnest foil commonly available is going to be 15 micrometers or so thick, probably too rough of a gauge to make it perfect. That kind of precision is why good adapters cost so much--and even they aren't perfect, just better.

Bottom line, for me: it looks like it is in focus, just not resolving as well as you'd like. There's a reason that Leica is making the 50 APO and Zeiss the Otus, and that's because current sensors can make even superb lenses like your 50 Lux look "bad." Add that the filter pack on the NEX-7 is in no way friendly to M lenses, and you see what you see. Personally, I despise my Metabones adapters as things in their own right, but they let me get the kind of drawing I want on a digital sensor that doesn't cost what an M 240 costs so I'm glad to be able to use them. Your lens seems to draw very nicely. Your kit probably can produce prints that rival medium format film, though with a much smaller size and far less hassle. Small compliment for a pixel peeper, perhaps, but I shoot Leica lenses for how they balance optical attributes to generate quality total images, not for MTF curves alone.

That all said, take a few similar pictures with either the top or bottom edge in focus. That should show the increasing resolution, as your corners are at 14.4mm from center. Note the difference in sagittal versus tangential resolution, and at different apertures. If all that lines up with the Leica tech doc, your lens is probably fine.

Hope this helps. Well wishes for good photography--

Jon



Nov 04, 2013 at 06:06 PM
adamdewilde
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p.2 #7 · p.2 #7 · Is there something wrong with this Lux 50 ASPH?


rscheffler wrote:
I don't think it's so much of an adapter problem, at least not one causing one side to go softer than the other because the image characteristics seen in the plane of focus on one side is pretty much the same as seen on the other side.

I'm kind of leaning towards the mid zone dip corresponding to the APS-C frame edge thinking, combined with possibly slight blurring caused by the sensor toppings at the image edges.

Michael Reichmann did a test a while ago that was somewhat controversial for his methodology, but should offer some insight into the results
...Show more


I sold my adapter for my X-E1 in prep for selling the X-E1, or else I'd go do the test now...
Let me see if I can dig up the Sony Nex M adapter, and I'll do the test again and see if my 50lux does that.. But AFAICR, it doesn't do that on mine.. At least not to the extent his does.



Nov 05, 2013 at 11:04 AM
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p.2 #8 · p.2 #8 · Is there something wrong with this Lux 50 ASPH?


fwiw, I took another look at Ron's test -- the truth is, the FE55 is looking sharper at the sides, and also seems to have similar OOF compared to the Lux (for what I can compare from shots in these tests).

These examples also seemed to show a smooth OOF for the FE55:
http://www.cameralabs.com/reviews/Sony_Alpha_A7r/sample_images.shtml






Nov 05, 2013 at 11:17 AM
rscheffler
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p.2 #9 · p.2 #9 · Is there something wrong with this Lux 50 ASPH?


sebboh wrote:
is there any chance you could post a full sized image from the m9 + lux similar to your foliage shot on the a7 (doesn't have to be too similar, just the basic idea)? this question seems to be coming up a lot...


Yes, I can do this, but probably not for a couple days. Also not sure if there are any leaves left on the trees/bushes nearby.



Nov 05, 2013 at 09:47 PM
sebboh
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p.2 #10 · p.2 #10 · Is there something wrong with this Lux 50 ASPH?


rscheffler wrote:
Yes, I can do this, but probably not for a couple days. Also not sure if there are any leaves left on the trees/bushes nearby.


thanks! i lose track of seasons here in SF, is winter already by you?

it doesn't matter much that is the same shot, just same basic distance. twigs are just as good as leaves. if you have something vaguely similar in your archives that'd be fine too.




Nov 05, 2013 at 10:21 PM
adamdewilde
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p.2 #11 · p.2 #11 · Is there something wrong with this Lux 50 ASPH?


Hmm... I just did a test with my M240, and the problem is minimal at worst. I did another test with my Nex, and the problem is a little worse, but probably not as bad as the OPs shot. so maybe focal distance plays a factor?

And I think it has more to do with field curvature then anything. Because I can usually hit sharp focus on a vertical shot when I focus and recompose, since I've used the lens long enough on an M240 (it's hard, but can be done).

Anyway, here is the NEX image:
[url]http://www.adamsalt.com/fm/lux50test.jpg[/url]


Basically the sharp focus area is lifting off the carpet into the air. Think of putting a string on the ground and lifting the two ends up and towards the camera. That's what's happening, since If I angle myself more in and twist my body, on that arcing motion, it changes where the sharp focus area is. Sorry hard to explain but if you have the lens you know what I mean.


Anyway, this is actually the main reason why I bought a 50APO...



Nov 06, 2013 at 12:26 AM
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p.2 #12 · p.2 #12 · Is there something wrong with this Lux 50 ASPH?


adamdewilde wrote:
Hmm... I just did a test with my M240, and the problem is minimal at worst. I did another test with my Nex, and the problem is a little worse, but probably not as bad as the OPs shot. so maybe focal distance plays a factor?

And I think it has more to do with field curvature then anything. Because I can usually hit sharp focus on a vertical shot when I focus and recompose, since I've used the lens long enough on an M240 (it's hard, but can be done).

Anyway, here is the NEX image:
[url]http://www.adamsalt.com/fm/lux50test.jpg[/url]

Basically the sharp focus area
...Show more


Thank you! That's very helpful!

Can you possibly post the similar test you took with the M240? It has been suggested that the falloff on the NEX is due to the mid-frame characteristics of the Lux -- so I'd be very interested to compare what happens on the M240 vs the NEX.

Is your Lux on NEX hard-stopping at infinity, with correct focus at infinity? Which adapter are you using? (Apologies if you've already said so.)

Roughly how far were you from the carpet?

Thanks again, this is great.



Nov 06, 2013 at 06:43 AM
adamdewilde
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p.2 #13 · p.2 #13 · Is there something wrong with this Lux 50 ASPH?


Haha... I can redo the tests tomorrow, and post both results, if you tell me what you require of me.

I think I was about 1.5m from the carpet, wide open. I was shooting to try and replicate your results of it being softer on the edges of APSC... In real life shooting the only issues I have with the 50Lux, Is the focusing and recomposing due to field curvature, again, the main reason why I bought the 50APO, was because I found in real world shooting, it was a lot easier to focus and recompose with then the 50lux. And I liked the look of the lens. But the 50Lux is great, aside from the field curvature.

The adapter was the cheapest thing you can get on Ebay, but it's pretty solid and seems to fit everything on very snug. Surprised actually at how high the build quality is. Infinity yes I can achieve it with the 50Lux, AFAIK, but I also have never had problem with the 50Lux on my M9p or any of the three M240 cameras I've had over the last few months.



Nov 06, 2013 at 09:52 AM
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p.2 #14 · p.2 #14 · Is there something wrong with this Lux 50 ASPH?


Oh, forgot to ask: which NEX? (I'm using NEX7)

If you find yourself in the mood, I'm most curious about:

1) if you try something like the rug shot with the Lux on both cameras, is the NEX-cropped version showing the mid dip at its sides -- meaning, does the M240 then get sharper again, and then fall back off at the far ends.

2) I'm not 100% clear -- i think you said infinity was fine, but just to be sure -- you reach the hard stop to get focus at infinity (meaning, you can't focus past infinity -- on both M240 and NEX -- is that right?)

btw, your mention of field curvature got me wondering, are there published charts that show the field shape? (In fact, I had been thinking fields would just be spherical, so that's a big deal that I didn't know yet!)

Thank you for taking time to help, -Scott



Nov 06, 2013 at 12:37 PM
adamdewilde
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p.2 #15 · p.2 #15 · Is there something wrong with this Lux 50 ASPH?


Sorry totally got caught up with work.. I'll get this done as soon as possible.


Nov 07, 2013 at 11:51 PM
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p.2 #16 · p.2 #16 · Is there something wrong with this Lux 50 ASPH?


Hah, you kidding? No worries if you can't get to it at all -- I appreciate regardless.

One question: your comment about field curvature -- is your expectation that you can focus and re-compose at f/1.4? It had never even occurred to me (unless subject is fairly far off).

So, Summicron vs. Summilux at f/2 is better for focus and re-compose? Is that what you mean?

Is there some sort of chart (like MTF) that shows the characteristics of field curvature?



Nov 08, 2013 at 08:01 AM
adamdewilde
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p.2 #17 · p.2 #17 · Is there something wrong with this Lux 50 ASPH?


Hi,

Yes again sorry.. It's just a few hectic days.

Yes, if you were to set the two lenses to f/2, you'd have a better chance at hitting focus with the APO.. This is what I've gathered from tons of portraits taken with both lenses. I don't know if the MTF charts support this or not. I have no idea about charts, I don't really read them. I usually buy and try, and then figure it out from there.

I was talking about the field curvature issue of the 50/1.4 with another forum member a while back (4 months ago). So I know others on here share my view. But I didn't realize that it would be that bad (your leaf shot seemed unusually bad). I'm gonna have to take a few more test shots as soon as I can.



Nov 08, 2013 at 02:32 PM
rscheffler
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p.2 #18 · p.2 #18 · Is there something wrong with this Lux 50 ASPH?


sebboh wrote:
is there any chance you could post a full sized image from the m9 + lux similar to your foliage shot on the a7 (doesn't have to be too similar, just the basic idea)? this question seems to be coming up a lot...



Here's a zipped folder from f/1.4 through f/11 with the 50 Lux ASPH. Not sure how much you can glean from these....



Nov 13, 2013 at 05:03 AM
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p.2 #19 · p.2 #19 · Is there something wrong with this Lux 50 ASPH?


rscheffler wrote:
Here's a zipped folder from f/1.4 through f/11 with the 50 Lux ASPH. Not sure how much you can glean from these....


Those do seem to hold up better out to the sides as compared to the similar shots with the A7 -- would you agree?

I'm assuming it's the same 50 Lux used both times? If so, then the difference comes down to the behavior of the A7 sensor, or possibly the M-to-E adapter.

I'm itching to know how the A7 and A7r compare. I've seen more color cast with the A7r, but it's my understanding that it's also possible the A7r will prove to have less smearing (eg, that color cast and smear might not always go hand-in-hand).

Thanks.



Nov 13, 2013 at 08:28 AM
rscheffler
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p.2 #20 · p.2 #20 · Is there something wrong with this Lux 50 ASPH?


Yes, same lens. I also shot the infinity scene with the M9 and six of the lenses I used for the a7 test, including the 50 Lux ASPH. Here's where I posted it on FM. The Lux ASPH and M9 combo does work better at the edges...

So far, from the little I've read recently about the a7R, it sounds like it might work better with 35mm and longer lenses. But I still suspect it will be lens by lens dependent.



Nov 13, 2013 at 11:51 AM
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