14-45mm f3.5 better for low light than 20mm f1.7?

I seem to have often read that the 20mm f1.7 is good for low light. It is unstabilised on a Panny body, however (I run a GH2), and I'm thinking that the 14-45mm f3.5 is probably better here. Aperture of the 14-45 (or 14-42) is two stops slower than the 20, but stabilisation gives it up to 4 stops advantage.

Allowing for the 14-45 closing down to, say, f4.5 at 20mm (making it 2.5 or 3 stops slower), and allowing for stabilisation only giving a 2.5 or 3 stop advantage in practice, it still means the 14-45 is at least the equal of the 20 for low light. So where does this logic fall down (smile)?

I show a graph illustrating this in another thread ( http://forums.dpreview.com/forums/read.asp?forum=1041&message=38303268 ), reproduced here.





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Lester

The advantage in image stabilization is purely an assumption varying by a multitude of reasons but faster glass is faster glass - period. Also image stabilization doesn't help subject movement. A person may be still for 1/30 but not for 1/4 . Now others may have more takes on this.

Regards,
Kurt

For some random samples:
http://www.pbase.com/khoss/
http://www.pbase.com/susanshaw
http://www.susanandkurt.blogspot.com
http://www.slshaw.info

gets in the way of practicality. Don't get me wrong, I love IBIS on our E-pl1 and how is stabilizes all my precious M lenses, but.....it only works on still lifes. Yes you can hand hold a 40mm lens down to 1/4 sec. (!) but if anything in the picture is moving you are out of luck. Many times you need to freeze at least walking motion (1/125 sec.) and here is where high ISO or fast glass (hopefully both) come into play. Fortunately, 4/3 benefits from slightly deeper DOF so using F stops faster than f/2.0 is still workable for most situations. FF is handicapped in this respect. Your GH2 has good high ISO capabilities, tie it to a fast lens (but not too fast!) and there is a lot you can capture that a FF can't!

Tedolph

Logic falls down when you slap the 20mm on a Pen and get the benefit of both main reason I went for the Pen.

No but the big difference is that a fast aperture means a faster shutter speed which generally means sharper images in low light, whereas IS just means the ability to use a slower shutter speed than usual.

Double them up for great effect!

--
Street Photography Blog:
http://fotofungi.wordpress.com/

tedolf wrote:

4/3 benefits from slightly deeper DOF so using F stops faster than f/2.0 is still workable for most situations. FF is handicapped in this respect.

tedolf said:

Tedolph

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Obviously subjective, being that this is a often a benefit from FF, like an extra string to a bow, Leica owners aren't cursing their equipment for giving them shallow DoF but yes deeper DoF on m43 can be just as beneficial at times.

A good reason that m43 is paired well with FF.

--
Street Photography Blog:
http://fotofungi.wordpress.com/

with e-pl1 i get 1/15 sharp shots consistently with 20mm lumix in churches/museums so it has a 1.5 stops of real IS and not the 3 marketing (although at times it can get to 1/8 second and still sharp but its only 50% of the shots and not 90% like at 1/15

I've a G1, the 14-45, and the 20mm. I use the 20mm indoors exclusively (or outdoors after sunset). I use the 14-45 outdoors before sunset exclusively. Practice has shown that this way I take the best pictures.

Could you use the 14-45 indoors? Sure, and in fact I did, before acquiring the pancake. It is quite usable. But it's not as good, especially with moving subjects (kids).

--
Florin Andrei
http://florin.myip.org/

The main reason this wouldn't work for me is that I'd still need slower shutter speeds. I often shoot in S mode and set to around 1/100 of a second for low light people shots. At night, if I don't use the flash I frequently find the camera bumping up to iso 1600 and 3200. With my e-pl1, it has nowhere to go beyond that. If I were stuck with a lens 2 stops slower, I'd be shooting around 1/25, and as a result most of my people shots would be pretty blurred.

Like an earlier poster said- why not go for the 1.7 lens AND IBIS? It's honestly the only m4/3 combo that satisfies me for low light quality. My kit lens is great, but only in good light or on a tripod.

compositor20 said:

with e-pl1 i get 1/15 sharp shots consistently with 20mm lumix in churches/museums so it has a 1.5 stops of real IS and not the 3 marketing (although at times it can get to 1/8 second and still sharp but its only 50% of the shots and not 90% like at 1/15

Click to expand...

Like you, I haven't been particularly impressed with the IBIS of the E-PL2. For me, the form factor of a G or GH body trumps the IBIS of a PEN, particularly in the normal to short-telephoto range (20-50mm). I can get about a 33% keeper rate at 20mm and 1/6s on my GH1 or G1.

I didn't rigorously test this, but using my GH1 and E-PL2, I did do some shooting around a bit with the Lumix 14-45mm lens at 25mm/4.9 and 1/10s. If I were to rank the combinations in terms of likelihood of a sharp result, it would be this--

GH1 + OIS > > GH1 + no OIS > E-PL2 IBIS > E-PL2 no IBIS

. . . Up to 4 stops stabilization is only available at longer focal lengths. At 20mm, I'd say say it's closer to one or possibly two stops. YMMV

I read Joe Posnanski's blog, http://joeposnanski.si.com/joe/ , wonderfully insightful comments about life and sports. Remembering his comments* on Internet posts, I usually start or reply to threads with caution, and am relieved to read the comments here (smile), thanks!

One of the touchstone issues of our era are the comments below stories that you see on the Internet. They are sometimes vile, hateful, racist and sexist. They are sometimes mean-spirited, vicious, anonymous and cold-hearted. They are sometimes so crude and painful that you can’t help but hope that you don’t live next door to any of these people ( http://joeposnanski.si.com/2011/04/11/commentary/ ).

In summary, I think folks have mentioned that stabilisation can't handle subject movement, that stabilisation is over-rated, that I should be shooting with a body I don't have (an Oly), and that the 14-45 otherwise works fine. So yes, I'd probably do as well with either lens on my GH2, remembering s=1/125 if anything is wandering about in shot...

In the mean time, I found the SLR Gear report on their IS testing of the Oly 520 ( http://www.slrgear.com/articles/is_olympuse520/IS_Test_Olympus_E-520_SLR_Body.htm ). They found 2.1 to 2.7 stop improvement, not 4:

"For the E-520, Olympus claims "up to 4 EV steps" of shake reduction, while the most either of our testers saw was 2.7 stops. While we wish the industry would adopt more believable performance claims for IS systems, we by no means single Olympus out in this regard: Our results here are very consistent with our findings for other manufacturers, both in terms of the amount of improvement claimed, and the amount we actually measured."

And they imply that in-body IS seems more effective at shorter focal lengths, while in-lens IS seems better at longer focal lengths.

--
Lester

lester11 wrote:
[snip]

lester11 said:

In summary, I think folks have mentioned that stabilisation can't handle subject movement, that stabilisation is over-rated, that I should be shooting with a body I don't have (an Oly), and that the 14-45 otherwise works fine. So yes, I'd probably do as well with either lens on my GH2, remembering s=1/125 if anything is wandering about in shot...

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I think the argument that image stabilization is only good for static subjects warrants some clauses because not all movement is noticeable in an image. It depends on how far away the subject is, as well as the movement speed and even the nature of the movement.

I've done a lot of low light, slow shutter speed photography of people, and I've frequently shot below 1/125 sec. So don't forget to experiment with shutter speeds. Sometimes 1/15 will work fine, sometimes it won't.

larsbc

If you stop shaking the camera the affects of image stabilization are reduced to zero.

A large aperture will gain you a faster shutter speed no matter what camera you put the lens on and no matter how hard you shake that camera.

IS prevents movement. It has nothing to do with low light capabilities. Stops of light absorption mean nothing when talking about IS.

--
GH2, GF1, & ZS3 Sample movies
http://www.youtube.com/user/mpgxsvcd#play/uploads
http://vimeo.com/user442745
GF1 Pictures
http://www.dpreview.com/galleries/4222674355/albums

The best IS is a steady hand and a little bit of care. IS is something I can live without in still pictures. A large aperture is not something I can do without.
--
GH2, GF1, & ZS3 Sample movies
http://www.youtube.com/user/mpgxsvcd#play/uploads
http://vimeo.com/user442745
GF1 Pictures
http://www.dpreview.com/galleries/4222674355/albums

mpgxsvcd said:

If you stop shaking the camera the affects of image stabilization are reduced to zero.

Click to expand...

mpgxsvcd said:

IS prevents movement. It has nothing to do with low light capabilities. Stops of light absorption mean nothing when talking about IS.

--
GH2, GF1, & ZS3 Sample movies

Click to expand...

but with IS you can shoot at lower iso which does affect speed in low light.

mpgxsvcd said:

IS [...] has nothing to do with low light capabilities

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I think the point I was trying to make is that IS allows a slower shutter speed. Perhaps I should have explicitly said that, for the sake of the argument, we assume the camera is not mounted on a tripod...

A slower shutter allows more light in. I think it is just maths that a stabilised lens which is two stops slower on aperture (say) but can fire four stops slower on speed because it is stabilised (say) allows shots in lower light for the same ISO.

--
Lester

lester11 said:

mpgxsvcd said:

IS [...] has nothing to do with low light capabilities

Click to expand...

I think the point I was trying to make is that IS allows a slower shutter speed. Perhaps I should have explicitly said that, for the sake of the argument, we assume the camera is not mounted on a tripod...

A slower shutter allows more light in. I think it is just maths that a stabilised lens which is two stops slower on aperture (say) but can fire four stops slower on speed because it is stabilised (say) allows shots in lower light for the same ISO.

--
Lester

Click to expand...

True, but in practical terms each lens has distinctly different advantages for low light depending on what you are trying to accomplish.

As has been stated the advantage of the wider aperture on a fast lens is that you can shoot at faster shutter speed that, when photographing moving subjects like people, is often needed to stop action. If they aren't moving much or can get them to hold still, you might be able to get a crisp shot at 1/15s... but 1/60s will be much better if they are moving...which is why the fast lens has such an advantage for candid photography. Then again if you want some subject blur you can get some cool shots at slow shutter speeds using stabilization.

Where stabilization has more value for me is if I am shooting something in low light where I want more depth of field and I don't need to worry about subject movement.

So I use the 20mm f/1.7 for photographing people in low light, but if I am shooting an architecture shot in low light maybe I'd rather use a smaller aperture, slower shutter speed, and stabilization to get the shot. A tripod or some kind of support would still be better, but for handheld I'd rather do that than shoot with too little depth of field.

And of course if you want shallow depth of field you are much better off with a fast lens regardless of the light.

The faster lens will focus much better, either auto or manual. At least on the PENs.

rpm40 said:

Like an earlier poster said- why not go for the 1.7 lens AND IBIS?

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Because I've no need for it.

In theory, it sounds like you must have IBIS for low light.

In practice, with the 20mm pancake on the G1, I never get camera-shake blur. The only blur I get, if any, is subject-motion blur, which does not depend on stabilization.

Theory is nice, but practice always trumps it.

--
Florin Andrei
http://florin.myip.org/

lester11 said:

And they imply that in-body IS seems more effective at shorter focal lengths, while in-lens IS seems better at longer focal lengths.

Click to expand...

Look, theory is nice, but practice trumps it. I did thousands of pictures with both the 14-45 and the 20mm on a G1 body in low light, many with subjects that are quite dynamic (kids playing).

The 14-45 is usable, but tricky. You'll get some good shots, but lots of duds too. I kept using it because I didn't have a better lens.

The 20mm is great. I managed to freeze people jumping in the air, no flash, just the normal indoors light. Awesome. I stopped using the zoom indoors after I got the pancake.

Regarding stabilization - the 20mm is so fast there is no blur at all from camera shake. Zero. The only blur I get is from moving subjects, and I've no solution for that (other than the f/0.95 Nokton or something) if I insist on not using additional light such as a flash.

--
Florin Andrei
http://florin.myip.org/