More tests of the G1/GH1 sensors

 

I was considering a rearrangement of my Lumix gear in favor of a G2. I like both my G1 and GH1 but have mixed feelings about each. On the other hand, selling both and grabbing something else is not financially practical! I therefore tried another test to see why I find a benefit to the GH1 sensor elusive. It rates higher at dxo's vaunted website, so something about it should be valuable!
Confining myself to indoor images, I found my wife's purse near a bright window and decided to see how the two cameras handled the absurd range. With both set to similar parameters (iso160, 1/10s f/3.2 using the Oly 17mm prime) I put the cameras on the floor and gave it a shot.
First up, the G1 is fainter for the same image. Its abilities to capture detail look similar but were hampered by that; I tried a second image with +2/3 EV, but that was much too much so discarded. I stuck the two RAW images into a Picasa collage, then boosted the fill light a bit. In this test, unlike the previous ones, the GH1 does look better. Its color balance holds up with less chroma noise, which had appeared before. This time I was more gentle in the fill boost, I guess, as the banding on the sensor was not apparent (I could see it with a larger boost though). Given this result I'm less inclined to let the GH1 go.. but a few more tests could be worth while.

k-x+1wk=OK+

A week into the K-x adventure.  Its size is mighty close to the Lumix GH1, though for the most part lenses are still larger.  Not all that much difference between the 45(50)-200 zooms, but crop factors make a difference in final image size, so it's actually a 90-400 vs 75-300 in 35mm terms.  Going to the Pentax 55-300 would tilt compactness back to the micro-43 camp, certainly.  The elder Sigma 17-70 is massive compared to the Lumix 14-45, but really I like the 17-70 in all other respects.  This is my 2nd copy after enjoying it on my A200 in 2009, so I knew I'd like it; in fact, somewhat to my surprise I prefer it to the Pentax 16-45, 18-55 and even 18-135 - so I'm glad it's back even at 450 grams.

I have the K-x set to auto-iso up to 5000, and its straight-from-camera images are similar to what I'm used to at 1600.  Truly a step up in sensor quality!  Here's a torture test at iso5000 - Raw image, lightly cropped but otherwise unprocessed:
This feels like a lot of dynamic range and reasonable color noise in the shadows for such a setting, and since it's a Raw image I could clean this up if I felt the need.  Wow.

70mm tests with the k-x

I put the Pentax k-x to work on a nice scene in the yard.  First up was the DA 50-200 WR at 70mm for a wet-leaf image, then the Sigma 17-70 (gen.1) - both at f/6.3 but auto WB/iso.  Looking at them overall I would take the 50-200 by a hair - but of course it's in its midrange vs. the extreme end so to some degree that's an expected outcome.  The background on the lower image is slightly more blue perhaps, and while exposure info is a match the DA-wr chose iso200, the Sigma 250.  I prefer the Pentax' choice.  It should also be noted that AF was engaged, and on the k-x one cannot be certain it chose the same focus point when multiple points are in play (I had AF-5point set).  When compacted by Picasa's collage tool it is very hard to pick a winner.

OK enough suspense: the top image is the 50-200.

kit changes coming (and Fast!)

I've made what amounts to my final adjustment in the Pentax gear.  I let the K200d and Tamron 18-200 go as a package, having found two excellent (I hope!) used deals.

The first was a K-x in 'excellent' condition for under $400.  I've enjoyed several excellent cameras in my recent past, but no camera with an excellent sensor.  Given this chance to see what one can do, I've allowed that to overrule my wish for a weather-sealed camera for now.  The more I read about this sensor, in the Sony A500 and k-x/k-r cameras, the more it appeals to me.  I really didn't want to step up to 16Mpixels, since several of my lenses may not be up to the capabilities of the A580/K-5 cameras - and my budget wasn't up for those anyway.  Having owned both 18-200 models now, I still feel that they are great for 10Mpixel sensors but perhaps best left there; it's a fun range, but with a great sensor I fear the images would not be well served by a do-it-all lens.  I can't say with any proof, it's just a feeling - but I'll go with that.

Deal number two was also surprising, and allowed the 18-200 to move on: a gently-used, 1st-generation Sigma 17-70 lens.  I owned this lens with my A200 and thought very highly of it: f/2.8 at widest setting, a reasonable f/4.5 at the long end, close focusing, very good sharpness and bokeh... it's a great package that I welcome back into my bag.  I was sure that I'd have one of these in Pentax mount when I first made the switch from Sony, but the DA 16-45 caught my eye for a while.  Its range was just too confining for me though, and the 18-55wr also caught me short on the telephoto end at times.  I like the concept of the DA 17-70, but the price on this Sigma was excellent.  The other temptation was another Sigma, the newer 18-50HSM that zooms and focuses internally; how interesting to see a lens in that range that does not extend while zooming!

I say these changes are coming Fast because I expect them to both be delivered in the next three hours!  I also received my new 72mm polarazing filter (shouldn't have sold the old one, I suppose) today, so it's a new kit all at once.  This should be fun!

An hour later, and the 17-70 is here.  How odd: I have no body to try it on!  Looks to be in great shape though, more compact than I remember. 

Well OK - the k-x came into town too late - it reached me at 8:15AM Saturday.  Wow, looks new to me - and oops, it came with a 4G chip inside!  Guess I'll check with the seller about that..