Panasonic GX7 Owner assessment - Part 4 - IBIS, Wide angles and DOF




I spent some time checking out the in-body stabilisation and after a lot of testing I discovered that the lowest speed I could hand hold the 7-14mm zoom at, with care, was 1/10th. sec. At this speed I could be confident of close to 100% success. This was indoors though and outside with a typical English breeze (i.e. gale!) I would obviously adjust that. So the IBIS does work, bit it is always the case with these things that any manufacturers guesstimates as to how many stops their IS gives you should always be taken with a pinch of salt. Firstly because we all have different levels of stability, which can of course be affected by how much alcohol, caffeine or other chemicals we have ingested or indeed how tired we are and secondly because we all have different standards as to what constitutes an acceptably sharp image. So you have what I'm capable of, make of that what you will.

One thing I also did was have a look at the difference between m4/3 wide-angle and Sony A7r (35mm / 'Full-frame') wide-angle.

Here's a comparison. 


The image on the left is the A7r plus Sigma 20mm shot wide-open at f/1.8. On the right is the GX7 plus 7-14mm zoom at 10mm again shot wide-open at f/4. And as you can see the pictures are completely different. Well, you might say, I knew that, but this is one of the reasons I dislike talking about equivalent focal lengths in different formats. I also dislike relating everything to some 35mm film base line. I don't think either of those things are helpful or useful other than to give a very rough guide as to what a lens may be able to cover. It does also depend on what you want. And for the most part I want the DOF that I get with the Panasonic. Apart from anything else because it's a shorter lens on a smaller camera, if I stand in exactly the same position using both camera / lens combinations I will get more in the frame with the m4/3 setup anyway. Particularly with lenses this wide.


Now in the above comparison the A7r / Sigma image on the left is a nicer looking file to me as the defocusing of the background concentrates on the plant, though it has to be said the Sigma 20mm isn't particularly sharp wide-open and needs a fair amount of PP sharpening. But as I said before I shoot very few images with poor DOF. There isn't really much sales potential in them for me plus I don't actually find them that attractive to look at apart from the odd picture.

Here's a picture I took yesterday. At first glance and at web size it may look like there is a lot of DOF. But the amount of the image that is acceptably in focus is actually very small.
I took this at f/5.6 at ISO 100 and 1/200th. sec. And all those decisions were based on the fact that I wanted absolutely the best quality I could get and it was very windy and I wanted the image pin sharp. So because of what I was using I made those selections and obviously had to live with them.
The GX7 / Olympus 17mm f/1.8 image above however at f/3.5 1/320th. sec. and ISO 125 does have everything acceptably in focus (acceptably to me that is) I was actually almost blown off my feet by the wind just before this shot, hence the high shutter speed. Now the Sony shot is undeniably sharper with higher resolution, but the Panasonic image is more what I usually want with my landscape, travel, location and architectural images. 

It is important to understand what we want and tailor our gear choices accordingly. I had the same situation when I was using film. I used both 6x4.5 and 6x6 cameras extensively, both of which have a lot less DOF than what is now called a 'full-frame' sensor. Standard lenses around the 75-90mm mark and super wide-angles only around 35mm-45mm gives pretty limited DOF even at aperures such as f/11 or f/16 which I was usually shooting on. And to a large extent this affected how I would frame an image. Picture buyers, in the main, do expect landscape and travel images to have the majority, if not all the image in focus. Apart from anything else it gives them more opportunity to crop. Plus differential focus landscape hasn't been regarded as particularly useful or attractive since the days of those horrible picture postcards with some out focus flowers always in the foreground. And I would select between MF and 35mm accordingly depending on what I anticipated I would be shooting. However, you can't always rule out the possibility that things may change and I'm certainly not capable of carrying three different formats around with me all day. Though if I'm away in a particularly attractive location I may have them in the car.

So despite all the seemingly attractive aspects of the 35mm / 'Full-frame' sensor, for me it's not always the right format for me. Sure I can work round it and make it work, but if by some miracle m4/3 sensors could have more pixels, higher resolution and better high ISO performance then there is no doubt that is what I would use exclusively. Come to think of if somebody can come up with a superb 1" sensor, then even better. I have been very curious about the Sony RX10 for example. However to date I've been somewhat underwhelmed by the raw samples I've found. I certainly like the idea of the camera and the specs. and I had lots of positive feelings about the Nikon 1's I was using last summer. The RX10 has an OLED viewfinder, fixed fast lens and all sorts of other goodies including IS and great video so it may be something I might consider. Certainly DOF wise it pushes a lot of my buttons. It is heavy though.

So there you go. Some musings on DOF and camera choices. But I've put off today's editing schedule for too long so it's back to Photoshop and the joys of captioning and keywording!!



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