Author Topic: Lumix G 20mm F1.7 ASPH. on E-P1 (Read 5187 times)

popo · « **on:** October 12, 2009, 03:07:50 PM »

I decided to start a new thread and not post in the sample thread directly as I want to comment as I go along.

The lens just arrived today. The lens was cheaper than average at my local dealer - turns out it was a kit split not retail box. For the saving I'm not going to miss the box. This might also explain their quick availability too.

Without any specific timing, AF speed seems comparable to the E-P1's kit zoom. The AF motor sound is totally different though. The Oly kit zoom has a more mechanical sound to it, whereas the Panapancake is a more electric hum.

And the most important detail: the looks! Images on the net made the gunmetal trim from the Pana lens finish look somewhat bad with the silver E-P1 body. As mine has a black wrap on it, the gunmetal doesn't stand out so much against the silver parts remaining so I think cosmetically this is an acceptable combination. I'll have to take a pic of that later. It feels a little odd seeing a Lumix lens cap on the Oly body...

Anyway, onto the pics!

Bokeh test:

f/1.7

f/2.8

Nice and round with the aperture wide open. Still great at f/2. Visibly heptagonal at f/2.8 onwards. Some outlining but not too pronounced.

While we're on the leaf, how about some 100% crops for sharpness? AF on the leaf. Note due to thin DoF the focus of the leaf isn't great wide open.

f/1.7

f/2.8

f/4.0

f/5.6

f/8.0

Flare

The sun is just out of shot on the top of this image. No flare but there is veiling glare in this example. I did see some flare while trying to compose this shot, but the E-P1 varies the aperture in LV so it could be at any setting which I didn't try here.

Vignetting and distortion

f/1.7

f/8.0

No obvious distortion here so I'm assuming the camera is correcting it well. Corner vignetting is apparent wide open, evening out at f/8. Most obvious if you look at the corners with the grass. I also found out my E-P1 tilt sensor needs recalibrating as it was telling me to point upwards just above the door which is obviously far above me.

Erm... some more random shots, all at f/1.7 except the fungi at f/5.6 for more DoF:

100% crop

CA

I don't have samples here, but CA. While I was playing with it at work, I shot the lights in the office I'm in and got purple fringing in the corners. Nothing else noticeable so far other than a little suspected LoCA when close focusing.

chronoguy · « **Reply #1 on:** October 12, 2009, 05:02:56 PM »

Can't wait for mine to ship from Amazon! It looks like you can shoot at 2.8 all day long.

count_zero · « **Reply #2 on:** October 12, 2009, 06:03:56 PM »

Nice shots. I keep waiting for Amazon to get this item in stock, but it's still pre-order only. By the time Amazon has it, Olympus will most likely announce their new lenses.

popo · « **Reply #3 on:** October 12, 2009, 11:18:10 PM »

Never mind f/2.8, you can shoot at f/1.7 all day

Maybe I didn't stress it clearly enough but the sharpness at 1.7 isn't as bad as it may look in the leaf crops as the DoF was very shallow. For less extreme close up shots it is fine.

I think I need to order an ND filter though... I was running into the fastest shutter speed at times shooting wide open.

Jman · « **Reply #4 on:** October 15, 2009, 08:42:51 AM »

In stock at Amazon now...mine will be here tomorrow. Can't wait!

popo · « **Reply #5 on:** October 15, 2009, 09:49:08 AM »

Time for a quick LoCA sample at f/1.7...

Looks ok to me, the longitudinal CA is quite weak, with only a slight green tinge in the back, red in front.

Now my attempt at sharpness testing, at various aperture settings, in corner and middle. 100% lossless crops from camera jpeg. Aperture priority, ISO400, IS off, tripod 2 sec delay. Manual focus on the part shown. Target is the back cover of a PS2 game.

Corner first, middle second. Note my corner is roughly equivalent to "border" in photozone tests, not extreme corner. I know I messed up trying to get them the same size making a comparison a little harder.

I left the camera on spot metering, so when the target was in the corner, what was in the middle was dark so the camera exposed longer. Thinking more, neither of these are that great in colour terms - the background should be white! AWB not the best in this case...

f/1.7

f/2.0

f/2.8

f/4.0

f/5.6

f/8.0

You can see the effect of corner vignetting in the exposure as you go down. The mid resolution is noticeably softer at f/1.7, improves noticeably at f/2, and is as good as it gets from f/2.8 onwards up to f/8 where it might be a little softer as diffraction kicks in. Similar story for corner, although quite subtle.

In all these pics, you can see what looks like sharpening artefacts around the text.

Unlike DSLR, the E-P1 can vary the aperture in live view mode so what you see isn't necessarily wide open. Therefore I can't be sure it was wide open and the focus is perfect wide open. This is a weakness of the E-P1 firmware 1.1. Maybe I can work around it with ND filters to help force it wide open, but that's for another day.

Here's the resized full f/1.7 images so you can see how they came out overall - resize only, no other processing.

Corner

Mid

Jman · « **Reply #6 on:** October 16, 2009, 12:04:03 PM »

I got my 20 f/1.7 today. So far, I'm really liking it. Focus is actually a bit slower than the 17/2.8, but it's fast enough for most stuff. It's optically superior, though. At f/1.7, the 20mm is sharper than the 17 at any aperture, and it does well at infinity too, which my 17 struggles with (I find the 17 very sharp close up, but it diminishes further away).

Some quick test pics. Crappy, dull, overcast day today, so nothing spectacular (and I didn't have all that much time to explore). Very impressed with the optics of this lens. It's nearly as sharp wide open as it is stopped down. Bokeh is very nice...best of the 3 m4/3 lenses I own. Purple fringing can be pretty bad at the corners on high contrast subjects, but I was mostly able to correct it in lightroom. It's really the only weakness of the lens that I can see so far. Very impressed.

The city, with a not so nice warning by the river, @ f/1.8:

Self portrait. Since I couldn't see where I was aiming, it locked on my mouth rather than my eyes, so that's the sharpest part, though my glasses are still in the DOF. This is wide open:

100% crop:

And finally a little bokeh test. Also wide open:

cosinaphile · « **Reply #7 on:** October 16, 2009, 12:39:56 PM »

whats with olympus lenses , they used to be great well made compact lenses in the heyday of slrs , and xa minirangefinders ,but now panny is making them look like also rans

the pannys 14-45 blows away the ep-1 s 14-42 kit zoom performance wise, now im reading the 20 1.7 panny outperforms the oly 17 2.8 at any apeture?

what gives ?

chronoguy · « **Reply #8 on:** October 20, 2009, 02:42:46 PM »

I just got mine... Some quick shots this afternoon,

sokar · « **Reply #9 on:** November 12, 2009, 06:21:35 AM »

In my case, the 20mm to the E-P1, the focus motor is always running Â¿? Bravo Olympus!....

PD: oh my God ...
http://forums.dpreview.com/forums/readflat.asp?forum=1041&message=33260046&changemode=1
Bravo Olympus!

Federico Alberto · « **Reply #10 on:** November 12, 2009, 11:08:01 AM »

In S-AF mode I haven't experienced any such difficulties...

I'd Better Hurry...

You've Lost It. Again...

I Feel AWFUL...!

Encamisado y Sra. en Nueva York

peterb666 · « **Reply #11 on:** November 12, 2009, 11:29:50 AM »

Quote from: sokar on November 12, 2009, 06:21:35 AM

In my case, the 20mm to the E-P1, the focus motor is always running Â¿? Bravo Olympus!....

PD: oh my God ...
http://forums.dpreview.com/forums/readflat.asp?forum=1041&message=33260046&changemode=1
Bravo Olympus!

Only if you have the thing set to C-AF which is the same as all MFT lenses. C-AF is hopeless on the E-P1 anyway.

sokar · « **Reply #12 on:** November 13, 2009, 12:02:56 AM »

In S-AF and C-AF. It occurs when there are large changes of exposure. Example: At night, at home, focus the TV and move elsewhere. But the quality is really good.

Lumix G 20mm F1.7 ASPH. on E-P1