GF 30 vs 32-64

Started 6 months ago | Discussions thread
left eye
left eye Senior Member • Posts: 2,270
Re: curves
1

norjens wrote:

left eye wrote:

The 32-64 has a major curved plane of focus.

Jim acknowledged that via the similarity between the lenses in question was only possible by using edge/corner AF focus when he tested the edge sharpness of the zoom.

In real-world use you normally focus close to the centre - and hope the edges will be sharp-ish! With the 32-64 they are not, with the 30 they are.

Enuf said.

For environmental portraits the zoom is great, defocusing edges while keeping your central subject sharp, yet bringing in really close details at the corners, magic if that's what you're after, otherwise the 30 is more predicable and overall far better ...if you only need to shoot wide without lens changes.

The zoom is sharp in the corners but ONLY much closer than the central-ish focus plane, otherwise the corners and sides will be poor.

Certanly the 30mm is far better than you might gather elsewhere compared to the 32mm end of the zoom. Just as the GF 50mm is a wonder compared to 50mm in the zoom.

I still don't see how this is a negative in general.

Generally a flat plane of focus is preferable - as then the plane of focus is predictable, flat is flat. A curved plane is somewhat of a irresolvable case - as to where the curve is.

Jim's tests while thorough, tested the 32-64mm sides and corners by focusing on them - rather then on the centre and then inspecting the sides and corners. Focusing on the sides/corners gives a best case scenario for the lens, but doesn't match up in my experience to real-world scenario. I've actually been very disappointed with the performance of the sides of this lens - due to the curved plane of focus. Sure when I focus at distance (near infinity) the corners render really close ground to be in focus - that's nice, but the sides at the same central near infinity distance are totally out of focus - disappointing.

I realise, and as I said, for environmental portraits some extra de-focus outside of your subject can be ok, but I'd rather just control this with aperture than a curved plane of focus.

The 30mm is far better in this regard than the 32mm end of the zoom - a fact that is hidden by Jim's test. In this regard I do think the 30mm has significant optical advantages over the 32mm end of the zoom. In fact for landscapes (horizons at middle to long distances) the 32mm end of the zoom is poor - due to the curved plane of focus, for closer subject - where an obvious horizon isn't present, the curved plane of focus becomes more integrated into the depth a scene.

As a landscape lens - I'd pick the 30mm every time, and the 23mm. For environmental portraits I'd pick the 32-64 zoom - due to FL flexibility - but I still wish it's plane of focus was flatter.

Sometimes I'd prefer my plane of focus to be flat and angled to the left or right, sometimes I'd prefer it to be curved away from me, sometimes flat and straight, etc. Some of those don't exist, but point is that in real life use I never have the perfect focus plane for my shot, and no particular shape is always better aligned.

If there's some repeating use case, one can be better. Like if you're scanning papers or paintings, you want a flat plane of focus. Same if you're testing lenses on standardized scenes, it's faster with a flat plane if your scene is flat. Alternatively if you're taking large group photos of people in a semi-circle so that everyone's the same size in the frame, you'd want a plane that is similarly equidistant; curving towards you.

@fkaphotoblogger indicated that it's for street and hiking photos, in which case the subjects can be anywhere in relation to each other. In that case the plane of focus might as well be shaped like a saddle for all I'd care.

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