Is Lumix 20mm f/1.7 lense (pancake) must have in addition to the 14-140mm?

The 20mm is a very nice lens, a great focal length for a slightly-wide field of view, and very fast. It's about 1 full stop faster than the 14mm. I've only read one review on the 14mm so far, and it wasn't all that flattering. Not sure I'm gonna bother getting it. But I do like the 20mm.
 
Ermmmm, I'd say so yes. But it does depend on what you intend on doing. Generally the answer is yes.
 
Of course, yes, itimjim makes a good point -- what do you plan on doing with it?

The 20mm is so tiny that it really, really mates well with the GH1/GH2 and turns them into basically pocket cameras. And it's pretty fast, about 2.5 stops faster than the 14-140, so it gets equivalent brightness in 1/5th as much light, so if you need a low-light lens it's something to consider. And it's (comparatively) cheap. And it can do autofocus, after a fashion. But if you really need a low-light lens, the Voigtlander 25mm f/0.95 lets in over 3x as much light as the 20mm f/1.7! It's manual-only and 3x the price, but, again, it depends on what you need. A tiny featherweight autofocusing lens? Or a manual-only superperformer that can practically see in the dark?
 
Barry_Green said:
Of course, yes, itimjim makes a good point -- what do you plan on doing with it?

The 20mm is so tiny that it really, really mates well with the GH1/GH2 and turns them into basically pocket cameras. And it's pretty fast, about 2.5 stops faster than the 14-140, so it gets equivalent brightness in 1/5th as much light, so if you need a low-light lens it's something to consider. And it's (comparatively) cheap. And it can do autofocus, after a fashion. But if you really need a low-light lens, the Voigtlander 25mm f/0.95 lets in over 3x as much light as the 20mm f/1.7! It's manual-only and 3x the price, but, again, it depends on what you need. A tiny featherweight autofocusing lens? Or a manual-only superperformer that can practically see in the dark?
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Both are in my purchases list. We are speaking about different focal lengths anyway. And the difference of more than 1.5 stop is huge with a substantial distinct outcome. Last but not least, the auto pancake is a bargain.
 
Barry_Green said:
But if you really need a low-light lens, the Voigtlander 25mm f/0.95 lets in over 3x as much light as the 20mm f/1.7!
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I couldn't quite believe this at first, and was all set to challenge you about it Barry. Three time the amount of light from f1.7 to f0.95?

If true f stops go like this:

22 16 11 8 5.6 4 2.8 2 1.4 1 0.7

Then we can expect, on paper, one and a half stops more light, and since each stop lets through twice as much light, yes 3x the number of lumens sounds quite a fair summary. Amazing!
 
The Voigtlander lets in more than 16x the amount of light as the Panasonic kit zoom at f4! When you put it like that, it really is pretty incredible.
 
I'm sort of interested on the 14 2.5 for steadicam or handheld shots. it also has autofocus which would be awesome :D
 
I don't see the point in that lens at all unless shooting in the dark. It is a single stop faster than the kit lens. At that cost, you could get that extra stop by upgrading from GH1 to GH2, for example.
 
Lucas Adamson said:
I couldn't quite believe this at first, and was all set to challenge you about it Barry. Three time the amount of light from f1.7 to f0.95?

If true f stops go like this:

22 16 11 8 5.6 4 2.8 2 1.4 1 0.7

Then we can expect, on paper, one and a half stops more light, and since each stop lets through twice as much light, yes 3x the number of lumens sounds quite a fair summary. Amazing!
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You missed one in there; f1.0.

And yes, the difference is a whole lot more than it sounds, isn't it!

I found a pretty handy tool online, the f-stop calculator:
http://www.computingbits.com/photography/fstop/Default.aspx

According to that, the difference between f/0.95 and f/1.7 is 1.67 stops. And since 1 stop = 2x as much light, and 2 stops = 4x as much light, you can calculate that 1.67 stops = actually 3.34 times as much light entering the lens. So it's actually more than 3x as much light. Pretty amazing.
 
Lucas Adamson said:
The Voigtlander lets in more than 16x the amount of light as the Panasonic kit zoom at f4! When you put it like that, it really is pretty incredible.
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Well, again, let's push it to an even more incredible level then ... because when you zoom the 14-140 to 25mm, it can't open up to f/4 anymore. It only opens up to a maximum of f/4.7.

So that means, 25mm to 25mm, the Voigtlander is letting in over 4.6 stops more light. 4 stops would be 16x as much, and 5 stops would be 32x as much, so... doin' the math... 4.6 stops = 25.6x as much light as the kit lens. Or, put another way, you'd need 1/25th as much light to be able to get equivalent exposure. The kit lens would need a 2,000 watt fresnel, to deliver the same brightness and exposure that the Voigtlander could get with a 75-watt lightbulb.

That's pretty crazy.

In fact, I do think I'm going to have to order me one now. :)
 
Lucas Adamson said:
I don't see the point in that lens at all unless shooting in the dark. It is a single stop faster than the kit lens. At that cost, you could get that extra stop by upgrading from GH1 to GH2, for example.
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The 2.5 is 1.333 stops faster, so letting in 2.7x as much light, which is not insubstantial! And it's tiny, as compared to the 14-140. If you have a real steadicam rig it won't matter (as the 14-140 is pretty small, overall) but if you're trying to use something like a Steadicam Merlin, it could sure make the difference. In general I haven't seen many reviews that totally praise the 14mm f/2.5 pancake, but I can certainly see where it would have some appeal -- it's a tiny, wide-angle, reasonably-fast lens.
 
The thing about the 20mm is that it is actually sharp wide-open. Is the voigtlander actually sharp at f/0.95? From what I've seen the answer is no. Whereas this is some stuff I've done with the 20mm wide open:

4565417254_382af145e2_b.jpg

4590959241_ccf6a792c3_b.jpg
 
Ben_B said:
Is the voigtlander actually sharp at f/0.95? From what I've seen the answer is no.
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Really? Are you perhaps confusing the 50mm Noktor with the Voigtlander 25mm? Because the Noktor, yeah, I've heard that goes quite soft when wide open, but I haven't heard anyone say anything like that about the Voigtlander 25mm. I searched around and found these pics comparing f/0.95 to f/8, and it looks pretty good...
http://soundimageplus.blogspot.com/search/label/Voigtlander%2025mm%20f0.95

This review shows some wide-open shots too, and they look pretty good.
http://www.luminous-landscape.com/reviews/lenses/voigtlander_f095_25mm_micro_43_nocton.shtml

Considering that I'd be using it primarily in video, it seems like it would be plenty overly sharp for an AF100. But yeah, if it's soft, I'd like to know about it before torching $900! :) I agree, the 20mm Lumix is totally usable at wide open, it's nice and crisp. I had heard the Voigtlander was the same way. Where have you seen it being referenced as soft at wide open?
 
Bloody Hell ... Thats Crisp !! I was actually toying with getting the 20mm but now my mind is made up.

Has anyone posted any footage using the 20 with the Teleconverter mode on the GH2 ? In theory that would make it a very compact 40mm 1.7 ( or longer ) with full Af, or is the St Emillion kicking in ?
 
Barry_Green said:
Really? Are you perhaps confusing the 50mm Noktor with the Voigtlander 25mm? Because the Noktor, yeah, I've heard that goes quite soft when wide open, but I haven't heard anyone say anything like that about the Voigtlander 25mm. I searched around and found these pics comparing f/0.95 to f/8, and it looks pretty good...
http://soundimageplus.blogspot.com/search/label/Voigtlander%2025mm%20f0.95

This review shows some wide-open shots too, and they look pretty good.
http://www.luminous-landscape.com/reviews/lenses/voigtlander_f095_25mm_micro_43_nocton.shtml

Considering that I'd be using it primarily in video, it seems like it would be plenty overly sharp for an AF100. But yeah, if it's soft, I'd like to know about it before torching $900! :) I agree, the 20mm Lumix is totally usable at wide open, it's nice and crisp. I had heard the Voigtlander was the same way. Where have you seen it being referenced as soft at wide open?
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Mainly from the wide open video stuff I've seen it doesn't look as sharp as it could be, still kicks the crap out of the CCTV "Noktor" though. For video it's probably fine...the 20mm is just spoiling me because of how good it is.
 
To answer the original question, YES if you wanna take photos with m43 body. That's the only m43 lens I own. I wanna add 14-140, too. The only thing I don't like about 20.7 pancake is its non-internal focusing mechanism. It's noisy, relatively slow AF, and adds constrains on focusing motor when heavy filters r added. I wish Panny releases 20.7 ii with internal focusing.
 
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