Panasonic 7-14 - Usage tips for UWA neophyte

Started Apr 19, 2014 | Discussions thread
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Anders W Forum Pro • Posts: 21,466
Re: Panasonic 7-14 - Usage tips for UWA neophyte

Florida Nature Photographer wrote:

Anders W wrote:

My "purple blob terminator" won't eliminate that kind of flare, just prevent it from going purple. There are other types of flare, from more diffused light, where it will help a lot though. You find a very good illustration of the effect here:

I had seen that as part of my pre-purchase study.


It will also help against purple fringing. But when you have the more or less naked sun rather than diffuse light hitting the front element, the only cure is to shield. I usually use my hand, or my hand suitably extended with something, like a gray card. It can be pretty tricky to do, especially if the sun comes from the right so that you have to use your left hand to shield from the right and you are shooting at the wide end, where the risk of getting your hand in the frame is greatest. It probably looks rather comical when you try to do it too. Glad I can't see myself when I am it.

Note that it may be difficult to spot the flare in the EVF (did you see it in this case when you took the shot?)

No, I didn't. I assumed the building had blocked it, and I didn't realize it could be an issue when the sun is behind. I thought the problem only occurred when shooting into the sun.

It isn't an issue when the sun is really behind you. But in this case, I guess it was actually a bit on the right and on top of you, enough so to hit the front element. Note that the reflections (four different spots) form a straight line. That's a sure sign that the flare is due to a concentrated light source, in this case the sun (although you can of course get the same from a spotlight too).

Perhaps you have already noticed that the front element of the 7-14 extends forward when you zoom out and retracts when you zoom in, so quite the opposite from most other lenses. This means that the problem is worst toward the short end where you have hardly any protection from the hood.

A couple of more things about how to deal with the flare (apart from trying to shield as best you can). First, it is sometimes possible to clone it out. If you have it in the sky, for example, that's usually pretty easy. A second strategy that I have seen mentioned (perhaps by kenw) but not tried myself yet is to shoot two frames at very slightly different angles, so that you get the flare spots in slightly different places, and then clone between the frames (i.e., borrow the problematic parts from the other frame).

As to the distortion with cylindrical things going oblong, that's to be expected at the edges as others have already told you.

O.K. So that is why it is only at the top. The top being an edge, the same as the left and right sides. I was hoping that it was my technique that caused that. I will have to remember to be aware of that.

I was practicing here at home this morning and I see that I can see the distortion in the EVF so I will watch for it more in the field.

Good idea. Also be aware that you can sometimes come to grips with it by using another projection, as I did in the courtyard shot. I use Hugin to go from rectilinear (the native projection of ordinary lenses) to Panini (or something else). Perhaps not what you want to do right now but worth keeping in mind for the future. Same trick as when you "defish" although in the opposite direction.

It's exactly the same phenomenon as with the arches in the example with the courtyard that I showed you earlier here:

And as I showed there as well, there are (at least sometimes) way to avoid it when you find it undesirable (as I often do). Remember that it's fine to play with the distortion of an UWA but there's also quite a few cases where that may not be what you want to or should opt for. I prefer to remain undogmatic in this regard.

I will have to become accustomed to its quirks, the same as I am with the 50-200 focusing issues. Not every lens can be a 12-40 I guess.

In this case, it isn't really to be blamed on the specific lens. Every UWA will be exactly the same in this particular regard.

BTW speaking of it, my testing confirms that 12mm on the 12-40 is NOT as wide as 12mm on the 7-14.

Not entirely surprising. Lens manufacturers frequently round a bit at the endpoints of the range, and for some odd reason, the rounding is always in a certain direction at the short end and another direction on the long.

Here are a couple of catches with the 7-14 from yesterday's little hike close to home. Would you have been able to tell that either of these are UWA shots if I hadn't let you know? And as you can see from the second shot, even the 7-14 can be pretty well behaved with regard to flare under the right circumstances.

The open oak fields ...

... and the deep woods

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