My latest lens buy is a bit unusual, so I thought I would post my findings here. For a start, it's an f4, which is pretty slow for a projection lens, but then it is a 400mm! Not only that, but it was also made to cover 6x7cm.
The Nuts and Bolts
A smaller Monster after a visit to Mr.Hacksaw
This is a Franke and Heidecke 400mm f4 projection lens (aka "The Monster") intended for use with F&H and Rollei branded medium format projectors such as the P11 and P66.
The lens is very light, this is due the aluminium alloy construction and the fact that it is a Petzval. I found this optical formula surprising, given the FL and coverage, I was expecting a Double Gauss derivative.
Apart from slow large format examples, film projection lenses tend to max out at about 150mm, with the occasional 200mm. The longest I have seen are rare 300mmms such as the triplet Hektor and Kalee Series S lenses, this is the first 400mm I have come across.
The Monster was 280mm long (originally!) and has a huge 110mm front element. The first obstacle to conversion was the non-standard 73mm tube diameter, which meant that none of my standard projection lens clamps would fit.
Second obstacle was a long "slow" focusing requiring a lot of movement, coupled with the back focus distance, this required the lens tube to be shortened to accomodate enough helicoid to be effective. After a visit to Mr.Hacksaw, the lens was about 26cm long.
Unusually, The Monster was absolutely pristine, perfect coatings and not even a dust speck internally, so there was no reason for me to strip it.........
........until I got it mounted and discovered that, despite the coating throughout, the contrast was poor. Looking through the lens revealed an internal black "satin" finish that was very reflective. No doubt this finish was adequate when used for projection, but with light now passing in the reverse direction onto a sensor, not so much.
So, I gutted The Monster and it now has a full Black 3.0 coating internally. To further improve matters I added one of my patented coffee bean tin lens hoods, and it was good to go.
It might look cumbersome, but it actually handles well.
Disassembly confirmed the Petzval diagnosis, with two air-spaced groups. Following the recent discussion on the forum regarding lens element edge-blackening I paid particular attention to this, only elements with concave faces were blackened. The factory-applied blackening was much less dense than the ink marker I use, and the coverage was patchy.
Handling
I have used lenses in the 400-600mm range before, but these were AF lenses with in-lens IS. Using the Franke & Heidecke "Monster" was.... a very different experience.
The Monster balanced well in my hands, its lightness and length meant that my left hand instinctively grasped it at the centre of balance of the lens/camera combo.
The size of the lens means that this one of those situations where you must support the lens statically and focus the camera. Thankfully The Monster is so light that this is not a problem.
Focusing is difficult, the IBIS, although smoothing vibration, causes the veiwfinder image to "jink" about, this is even worse in magnify mode, and the f4 aperture means the DOF is tiny. Switching IBIS off trades the jinking viewfinder image for a smoothly wobbling one, which is just as difficult to focus with.
On the plus side, the "slow" focusing means that there is no problem getting spot-on focus.......... if you can get a viewfinder image stable enough to achieve this.
Framing was also a problem, I found myself constantly walking backwards to get the subject to fit the frame. It seems my inner frame-o-matic wetware is calibrated for 200mm and under.
The focusing range with my setup was infinity to 7m. At closest focus the frame short axis is only 180mm, so not many subjects will fit in, which is just as well, as at this distance the DOF is tiny.
Because of the frame size limitation, I rarely took any shots closer than about 12m.
The Image
The Monster has good contrast (at least it does after my mods), and will trigger focus peaking easily, it is also quite sharp, although I do have projection lenses that are sharper. Another plus is that the output responds very well to USM in post.
The best background separation I managed with The Monster.
Sharpness is very even across the frame, this not surprising as The Monster was designed to cover 6x7cm, so my tiny FF sensor is only seeing the very centre of the field. The image circle is large at about 150mm, so the lens might prove useful to the large format bods.
I could not detect any field curvature, which is unusual as Petzvals are the Poster Children for this. The lens has been produced visually unchanged since 1960, therefore it is probably too old to have benefited from computer optimisation, so I'm suspecting the large FL and coverage are the likely causes.
What is he going to do with that Hazel nut?
There is none of dreaded "Petzval Focus Fringeing" and peak contrast coincides exactly with peak sharpness. Standard chromatic aberration is non-existant after ACR, but longitudal chromatic aberration (LOCA) is present and strong, but after all, this only a four element Petzval. The LOCA manifests as green fringeing on edges behind the focus point, this is mainly a problem on urban subjects, as a leafy background disguises it well.
Purple fringeing on high contrast edges is very rare, I only saw it once.
Nice 3D depth in this shot.
Not as much subject isolation as I expected.
The subject separation is not as pronounced as I was expecting for a 400mm f4. I suspect the reason for this is that all of my other longish projection lenses are Petzvals that do have extreme field curvature. With these, focus becomes much closer as you move from a central in-focus subject to the frame edge, this throws the background dramatically out of focus and massively increases perceived subject isolation.
The Bokeh
The bokeh is of the "smooth blur" flavour which seems to be the type popular with the majority of users, unfortunately, I prefer bokeh with character, texture or patterning.
No swirl or bokeh texture here.
There is no swirl, and I mean, none - at any distance or focus. The lens is a good bubbler with small specular sources, and the bubbles have soft unlined peripheries. Bubbles are not as large as I was expecting for a 400mm f4.
Close up, backgrounds just melt away.
No swirl and very little bokeh texture here.
The Bottom Line
There are difficulties focusing and the bokeh is not the type I am looking for. The FL limits the subjects the lens can be used for, if I fill the frame with my usual smallish subjects, the background is simply Not There, no interesting bokeh texture, it's just blurred into feaureless nothingness.
Using the lens for people means a very long distance for full body, which although great for candids (if they're not moving!), also reduces subject separation from even distant backgrounds. This is further exacerbated by the flat field.
Basically, the lens does nothing that my longer AF lenses cannot do better.
The only thing that may have given The Monster an edge was its f4 aperture, but even this this failed to give the subject separation I was expecting.
The most enjoyable part of getting the lens for me was doing the adaptation.
I think that this sums up my take on The Monster:- because of the non-standard tube diameter I had to kludge up a mounting solution, with the intention that after seeing what the lens could do, I would create a more robust fitting - I ain't going to be doing that.
