50mm f40 Pan-Focus Lens

[Chriscrawfordphoto]

When I was a kid, I remember seeing an article in Popular Photography about a new lens that had just been introduced called the Itorex Pan-Focus Lens. It was a T-Mount 50mm lens with a fixed aperture of f40. There was no focusing mechanism because it was claimed that the small aperture made EVERYTHING in focus.

It sounded cool, but I was a kid and didn't have the money to get one. Fast forward 30 years later, and I thought of that article, and went to eBay. Got one, new in the box, for $25. Had to get a T-mount adapter for my Canon EOS 5DmkII, which set me back $9.

It turns out that you can unscrew the rear lens group and removed the aperture, which is a metal disk with the f40 hole in it. This makes the lens into a soft-focus lens! I just got it a few days ago and have not used it for anything serious, just some quick shots in the yard to try it out.

With the aperture in place, everything from about 2 feet out to infinity is in focus, but diffraction takes its toll....fine detail is very soft.

Here is the lens

These two are full-frame images with the aperture disk in place.

This is a 100% crop of one of the above images, showing the resolution with the aperture in place.

These three are with the aperture disc removed. I really like the soft focus effect here. It still has fairly good depth of field, despite the larger effective aperture. I did find the images looked sharpest at distances closer than about 10 feet.

The aperture disc is rather thick, and I think that also contributes to the low sharpness and diffraction. A hole in a thinner piece of metal would probably be better. I really like the soft-focus effect, and I think it has potential to make some very interesting images.

 

[B-9]

That's pretty neat Chris, I'm sure you'll find a way to turn a few prints from it!

 

[farlymac]

The soft focus stuff looks very good, Chris. I used to have a Polaroid 110B that had an f90 aperture in the flip-up built-in lens cap, with similar distance in focus. I used the measuring tape that came with the close-up kit to set the foreground subject at it's nearest focal point. I didn't notice a problem with diffraction shooting the 3000 speed B&W roll film, but then my distant subject was only about fifteen feet across the room. I would have messed around with it some more, but my stock of film was going bad, and was no longer available.

PF

 

[zuiko85]

That is interesting Chris, never came across that one before. I do seem to remember a lens that had regular aperture control but you could swing in a very small waterhouse stop for "infinite" depth of field. There were lots of interesting gadgets in those days, Spiratone had a 2 whole pages of keen stuff back in the day.

 

[_goodtimez]

You may achieve the same results using the bottom of a wine bottle 🙂

 

[Chriscrawfordphoto]

You may achieve the same results using the bottom of a wine bottle 🙂

I don't drink wine, and besides you can't mount a wine bottle on a camera 😀

 

[btgc]

I like soft focus images more, probably just because of effect but still. I would like to try some SF shots using thin coat of vaseline on front element, it is described as standard technique back then. I just have to decide which lens will be used 🙂

 

[Chriscrawfordphoto]

I like soft focus images more, probably just because of effect but still. I would like to try some SF shots using thin coat of vaseline on front element, it is described as standard technique back then. I just have to decide which lens will be used 🙂

Get a cheap UV filter and smear the vaseline on it; You'll have a hell of a time cleaning it off a lens, and it might damage the glass. Putting it on a filter works just as well and ruins a cheap piece of glass, not a costly one!

 

[DominikDUK]

The Vaseline effects and the effects given by a true soft focus lens are very different. A vaseline smear simple creates an unsharp photo whereas a true softfocus often has a sharply delined photo with an overlay of unsharpness caused by optical faults. Some SF lenses are Dialyts and they are very sharp lenses which can be seen if said lenses are stopped down. Many SF lenses are dual use lens soft when wide open sharp if stopped down. Some are meniscus lense but even they sharpen up if stopped down. The Vaseline results in a smeary look which suits some subjects but again doesn't even look close to the effect created by an SF lens

 

[Chriscrawfordphoto]

The Vaseline effects and the effects given by a true soft focus lens are very different. A vaseline smear simple creates an unsharp photo whereas a true softfocus often has a sharply delined photo with an overlay of unsharpness caused by optical faults. Some SF lenses are Dialyts and they are very sharp lenses which can be seen if said lenses are stopped down. Many SF lenses are dual use lens soft when wide open sharp if stopped down. Some are meniscus lense but even they sharpen up if stopped down. The Vaseline results in a smeary look which suits some subjects but again doesn't even look close to the effect created by an SF lens

This lens I bought seems to give that classic soft-focus look. I haven't tried the vaseline trick myself; in the past I used Tiffen Soft-FX filters, which are nice too, but not nearly as strong an effect as real soft-focus lenses are.

 

[btgc]

Filter, hm. Look, what happens when I post before waking up. Filter, that's so simple!