Petzval character

[Charles Twist]

This started on another thread, but is better as a stand-alone.

Do you reckon a projection lens would swirl in the centre of the image, behind the focussed subject? I know my lens is a camera version, but it really only swirls in the farther reaches of the image circle and then not always. For portraiture, the close focussing increases the image circle and reduces the probability of me seeing any swirling.

Re Petzvals generally: (i) They are very subject to glare. They need a proper lens hood and you have to apply that old maxim: don't shoot in to the light (which isn't true really any more with modern lens coatings). I'll pull out a shot of an arc welder at some stage - interesting... (ii) The focal plane is curved outward, which is a bit trippy.

Best regards,
Charles

[Marizu]

Charles

re 'projection lenses'. I would look at this from another direction. 95% of the petzval proj lenses that 'swirl' that I've seen during the past couple of years, say 50 +, are very short in fl - on average 5/5 1/2", ok they're fast but they're only really useful for quarter plate or 4 x 5 at a push for decent portrait work

I'm assuming that you're focusing on 4 x 5/5 x 7 for this work??, and so there may well be no need to consider this?

regards

andrew

Andrew as (mis?)quoted by me is pretty much spot on and that is one of the reasons that I am not overly enamoured with their indiscriminate use.
They are more likely to swirl in the extremities of their coverage so people shoot shorter focal lengths to make this happen.

Petzvals get expensive in their longer focal lengths and this pushes people towards shorter lengths which make many of the tight facial portraits look a bit bug eyed. Maybe this is the '3d quality' that people refer to.

Petzval is a lens design. Projection petzvals are the same but they don't have slots for waterhouse stops.
I have a couple of projection petzvals and they shoot great.

[Andrew Plume]

thanks Marizu

yes, they certainly do swirl in the extremities of the coverage

apart from the current interest in wet plate work, which has surely pushed up the prices of 'proj petzvals', people seem to be very taken with 'the Aero Ektar swirly look' and as decent 'AE' lenses go for pretty high prices, I'm assuming that the proj petzvals are a cheaper way in, albeit without (on the whole) any stops

regards

andrew

[Charles Twist]

The expensive Petzvals tend to be the f/3 ones. I picked up a 12" f/4 for £450. For how much are the 8" f/4 selling now - £250?
Do the f/3 Petzvals swirl more? Or does the wide-field component merely result in greater blurring?
Thanks,
Charles

[Andrew Plume]

Charles

yes, probably one of the better known examples of a f3 is the much vaunted Dallmeyer 3B, which from memory isn't 'overly swirly', although there's plenty of examples of it's work available on the web

regards

andrew

[Marizu]

The expensive Petzvals tend to be the f/3 ones. I picked up a 12" f/4 for £450. For how much are the 8" f/4 selling now - £250?

Good grief!!!

I forgot to mention, projection petzvals have little (or nothing) in the way of lens shading so you need to shade them yourself or be very careful with regard to flare.

Many use the 3B and its 11.5"(?) focal length on 10x8. Ideally, for half body through to headshot, I would personally be looking for a 24" or possibly 18" to keep the ears in the picture. Those lengths rarely come cheap and they tend to be f5 or slower.

[Andrew Plume]

........exactly

one lens, that will do the job on 10 x 8 and which has a 24" fl, is the Dallmeyer 6D, with a speed of f6, it's not cheap at all, stated coverage is 12 x 15, I couldn't envisage ever using mine, so I cashed the chips in

regards

andrew

[Alex Timmermans]

You don't really need a 24" lens for 8x10
A 3b sometimes is to short indeed.
Nowdays i make my portraits mainly with a Hermagis 420mm 4.5 petzval which is an awesome lens.

And many projection lenses do have a shade.
I have a 20" Hermagis which has a large shade but nog water house slots.

Although it is a petzval lens it doesn't mean they all swirl.
I have some which swirll a lot. And other hardly swirl.
The cheaper lenses, like magic latern lenses, swirl more than the better brand lenses.
Also Jamin Darlot cone lenses tend to swirl more than the normal petzvals.
But only when used on larger plates than they were made for.