G1X landscape focussing questions, advice appreciated

Started Aug 29, 2012 | Discussions
Rich the Hiker Regular Member • Posts: 451
G1X landscape focussing questions, advice appreciated

Hi, looking for some views on taking focussed landscapes with the G1X with a decent depth of field to get a lot of the image in sharp focus.

Think i've read here that most users will use G1X at aperture values 4 or 5.6 as this the lens sweet spot...for greater dof i'd need to use f8, f11 or even f16 with the complication of diffraction etc.

1) Has anyone tried f11 or f16 and were the results good for landscape, bearing in mind that the G1X has very poor close focussing anyway....guess it may be a few metres at f11 or f16 at 28mm focal length.
2) Anyone ever tried focus stacking? Ive heard of it but never tried it.

3) Is there any free focus stacking software or is it something that is usually only part of a v expensive Photoshop CS5 etc package?
4) Would focus stacking be beneficial for great dof for some landscape shots?

5) any idea what the closest focusing distance is for the G1X at f11 at 28mm, so that interesting foreground would be sharp?

6) When shooting landscape do you guys shoot to focus on the interesting foreground, or do you aim a third into the photo at the hyperfocal distance..??? not sure about this either.
Thanks
Rich

Rod McD Veteran Member • Posts: 6,578
Re: G1X landscape focussing questions, advice appreciated

Hi Rich,

The G1X's real FLs are 15mm - 60mm, (giving 28-112 in 35mm equivalent FOV). My experience is that if I simply rely on the Auto or P modes, I don't always get the DOF I need for landscapes and groups of people and other subjects with any depth. I've found that I have to 'think DSLR', (even though I'm shooting a camera that has the ergonomics of a compact). With a deep landscape, I've found that they may give the focal point in focus, but detail in front or further back may be out of focus. I've also found that my G1X program modes (Auto and P) favor shutter speed over DOF. By this I mean that I see it selecting higher shutter speeds and stopping down less than I would have chosen myself. So, I switch to 'A' mode and stop down further than the camera's program in quite a few situations.

I ran some test shots in my front garden to see the effect of stopping down on the resolution of detail. The lens does improve a little stopped down a stop or so, but only a little. My honest opinion is that its performance is excellent and remarkably even across the range of apertures right through to f11 & f16. Sorry, but I ditched them all. But just test your own camera..... Set it up in good light on a heavy tripod in A mode and take the same image at every aperture. Then do the same in Auto, P and Scene Modes (set to Landscape) and see what aperture and speed combinations it gives you. And you can repeat this at different ISOs. It doesn't take long and you'll soon see how it reacts and performs.

If I'm seeking to extend DOF, I either stop well down, select the point I want in sharp focus using the AF green square and recompose. Or I do sometimes select a point about a third in, but I'm not too careful about this. I guess I just do it by experience, but that's not hard at the WA end of the zoom range. 15mm just has so much inherent DOF. I could go to MF, but I don't do that often - I have my doubts whether the little scale on the LCD allows much greater accuracy than using the AF green square and recomposing.

The G1X provides for focus bracketing, (see p115 of manual) but I haven't used it. It might be very useful if you have a scene that is demanding in terms of DOF and you know you might not be back for a long time....... As for focus stacking, I'm not much into PP and haven't tried it.

You can get good approximate DOF from DOF tables - which you can google. Sorry I don't have a link. (Someone else might be kind enough to provide one). However I'd advise a certain amount of caution - the DOF table formulae incorporate a variable factor called the Circle of Confusion (the COC) which is adjusted for sensor format and print size. They can be confusing and sometimes misleading. I'd suggest noting what DOF the table suggests at several key FLs and at several useful apertures and try it out.....

Hope this helps. Cheers, Rod

 Rod McD's gear list:Rod McD's gear list
Canon PowerShot G1 X Olympus Tough TG-4 Fujifilm X-T1 Voigtlander 90mm F3.5 APO-Lanthar SL II Fujifilm XF 35mm F1.4 R +10 more
RAMSII Regular Member • Posts: 224
Re: G1X landscape focussing questions, advice appreciated

The G1X is included in the Depth of Field Calculator tables at http://www.dofmaster.com/dofjs.html . Circle of confusion is shown as 0.016 mm.

Richard

OP Rich the Hiker Regular Member • Posts: 451
Re: G1X landscape focussing questions, advice appreciated

Thanks for the great advice Rod, and for explaining it all so I could understand it (or most of it). My understanding of stopping down is reducing the aperture such as from f2.8 at 28mm to f8 aperture at the same focal length - is that right?

I din't realise the G1X does focus bracketing....I'll have to look that up, perhaps it is to aid focus stacking for greater DOF?

This G1X has to be handled like a DSLR as you say for focus and DOF reasons, so I need to get into that mindset.
I just ordered a B+W MRC Circular Polariser for it : )

John Kirby
John Kirby Junior Member • Posts: 26
Re: G1X landscape focussing questions, advice appreciated

An article in Wikepedia has a list of software available for focus stacking, some of which are General Public Licence, i.e. free: http://en.wikipedia.org/wiki/Focus_stacking .And there's a heap of stuff if you just Google "Focus stacking software"

h2k Contributing Member • Posts: 901
Re: G1X landscape focussing questions, advice appreciated

Ramsi and John, thanks for some interesting links!

Dale Cotton Senior Member • Posts: 1,937
Re: G1X landscape focussing questions, advice appreciated

You already have the essential idea that there is a conflict between the sweet spot aperture for a lens and the goal of maximizing DOF. You already have excellent input from the previous responders, and I've never used a G1X, but certain principles nevertheless apply, simply based on sensor size and focal lengths.

Every lens and focal length has its sweet spot for highest resolution at the plane of focus (usually called the "point" of focus). This is traditionally in the f/4 to f/5.6 range. Wide apertures, such as f/2, tend to be a little softer due to design difficulties. Smaller apertures such as f/11 or f/16, tend to be softer due to diffraction blur. But with really small pixel sizes in the sensor, for example a point & shoot camera or a larger sensor camera with a really high megapixel count, diffraction kicks in at ever wider apertures.

When the goal is to maximize DOF you have to find a compromise between the aperture value that maximizes the resolution at the plane of focus and an aperture value that gives you plenty of DOF. I think you'll find that f/8 is that compromise value for your G1X, but as Rod said, you really should test this for yourself:

Find a location that has objects at all distances from a few feet to several hundred yards where you can work without interruption. A really large mall parking lot filled with cars or a really long picket fence or a long city street or a long, straight stretch of railroad track are all ideal at least so far as subject matter goes. Mount your camera on tripod, manually focus maybe three yards into the scene, then take a series of shots at f/2.8 f/4, f/5.6, f/8, f/11, and f/16 at 28mm, 35mm, 50mm, 75mm, 100mm, and 112mm. (Of course some combinations will not be possible since max aperture gets smaller as focal length gets longer.) Now repeat the same sequence but this time with your focal point significantly deeper into the scene. If you have the patience, repeat again at an even deeper focus.

Now you go back home and examine all shots on your monitor at 100% magnification. Which is easy to do in some software and impossible in others. You'll learn several things from this procedure: One is how close to the camera you can focus at various apertures and still have an acceptably sharp distant background. Another is which aperture you want to default to as your preferred compromise between sharpness near the plane of focus and sharpness at significant distances from the plane of focus. Another: you'll learn which apertures you want to avoid altogether for landscape work. For example, you may decide f/2.8 is always too soft at one end and f/16 is always too soft at the other end. Yet another is how much DOF decreases as focal length increases.

Actually, just doing a procedure like this is the sort of thing that separates the men from the boys, so to speak. So whether you actually do the procedure or not will tell you which of those two camps you fall into.

*

Incidentally, focus bracketing is most likely intended to allow you to choose which of the frames works best during post processing. That it can also be repurposed for focus stacking is pretty neat if the results are good enough. Nevertheless, I would think you'd have to take into account subject motion, such as a slight breeze through the leaves of trees, or waves in water, or even clouds moving across the sky.

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Dale Cotton, Canada
http://daystarvisions.com

Petes Contributing Member • Posts: 976
Re: G1X landscape focussing questions, advice appreciated

Hi Rich, I get good dof with f8 and f11 for my landscaping shooting in raw. 12x18 prints with some cropping to get to the 3:2 ration look very nice.
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Pete Smith
http://www.pbase.com/petersmith

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