[slackercruster]

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What kind of soft focus lens can be put on a 645? I got a single element soft focus lens for my K-x. Produces dreamy images like this.





They have a 67 soft focus that can be adapted to the 645. Anyone try it? What does it do?

Someone mentioned putting a single element lens on a bellows. Any ideas?

Thanks

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Last edited by slackercruster; 06-18-2012 at 11:53 AM.

[RioRico]

Someone mentioned putting a single element lens on a bellows. Any ideas?

That works. One approach is to use +dioptre close-up optics on extension. A +10dpt meniscus becomes an uncorrected 100mm lens. (Effective aperture depends on diameter and mount.) A +8dpt Raynox DCR-250 becomes a somewhat corrected 125/3.2 lens. I'm playing with the front element from a Polaroid Pronto! camera, probably 60/2 although it's more like 60/2.5 the way I've mounted it. This meniscus gives a VERY soft and PF-full image, probably much more than you'd like. Of what I've used, the Raynox gives the most satisfactory results.

Of course, one old soft-focus trick is just to smear a clear filter with some Vaseline. Or nose grease.

[JinDesu]

Of course, one old soft-focus trick is just to smear some Vaseline on a clear filter. Or nose grease.

I just give it a little front focus. Nice and soft and bloomy.

[slackercruster]

That works. One approach is to use +dioptre close-up optics on extension. A +10dpt meniscus becomes an uncorrected 100mm lens. (Effective aperture depends on diameter and mount.) A +8dpt Raynox DCR-250 becomes a somewhat corrected 125/3.2 lens. I'm playing with the front element from a Polaroid Pronto! camera, probably 60/2 although it's more like 60/2.5 the way I've mounted it. This meniscus gives a VERY soft and PF-full image, probably much more than you'd like. Of what I've used, the Raynox gives the most satisfactory results.

Of course, one old soft-focus trick is just to smear a clear filter with some Vaseline. Or nose grease.

Yeah, I gave up on grease a while back. You have any sample SF photos from your setups to post?

[RioRico]

Yeah, I gave up on grease a while back. You have any sample SF photos from your setups to post?

I'll see if I can get some up, but it may take awhile.

[slackercruster]

I'll see if I can get some up, but it may take awhile.

OK, that would be fine.

I did think that if a guy is going the grease route to do this. Get a dedicated junk lens. Coat the filter on the *reverse side* and that way the grease will stay put as well as your effect from the grease as you like it to be. Just don't store it in the heat or the grease may run.

[slackercruster]

That works. One approach is to use +dioptre close-up optics on extension. A +10dpt meniscus becomes an uncorrected 100mm lens. (Effective aperture depends on diameter and mount.) A +8dpt Raynox DCR-250 becomes a somewhat corrected 125/3.2 lens. I'm playing with the front element from a Polaroid Pronto! camera, probably 60/2 although it's more like 60/2.5 the way I've mounted it. This meniscus gives a VERY soft and PF-full image, probably much more than you'd like. Of what I've used, the Raynox gives the most satisfactory results.

Of course, one old soft-focus trick is just to smear a clear filter with some Vaseline. Or nose grease.

So, is this what I would use Rio?

Novoflex Adapter Connects the Universal Bellows to Pentax 645 Medium Format Cameras.

What single element lens fits on the front of the bellows?

[RioRico]

So, is this what I would use Rio?

Novoflex Adapter Connects the Universal Bellows to Pentax 645 Medium Format Cameras.

Yow. That is expensive. I take it you don't already have a P645 bellows? One problem with using such a bellows is its depth. It probably doesn't compress to less than 40mm. Add the P645 register of almost 71mm, and you won't be able to achieve infinity focus with anything shorter than a 115mm optic. There's a solution: an M42 focusing helicoid. See below.

First, we need a lens mount. My usual budget approach would be to find some screw-->P645 adapter -- but I don't see any inexpensive ones of any kind on eBay. Mount-reversal ring, plain macro tubes... nada, nothing, zilch.

So my next starting move would be to look for a trashed lens, and remove its mount. Do any other MF bayonets physically fit the P645 mount? Lacking such, another possible starting point is a P645 body cap, and I *do* see one of those on eBay right now for ~US$30.

Next step: turn an adapter or salvaged mount or body cap into an M42-P645 adapter. If an existing adapter has threads, step rings can be used to get to M42. Otherwise, an adapter or salvaged mount can have a wide-flange M42-PK adapter glued to it. The body cap is even simpler: cut a hole in it, into which an M42 male thread will fit. I would insert a shortest M42 macro tube section, thread it into the hole, then glue it in place.

Now we skip the expensive and too-fat bellows and go lean: an M42 16-35mm focusing helicoid, about US$60 shipped from Shanghai to USA. Thread that into the M42 female mount we've attached to the adapter or body cap. On the front of that, add a step-up ring to get from M42 to the optic's diameter.

What single element lens fits on the front of the bellows?

I suggested either a +10dpt close-up meniscus (FL=100mm) or a +8dpt Raynox DCR-250 (FL=125mm). With my 49mm +10dpt optic (US$10 shipped) I use a 42-49mm step-up ring. With the Raynox (rear thread is 43mm) I use a 42-43mm step-up ring. The Raynox gives better images. The meniscus is cheaper.

The cheapest combo would thus be:

camera --> P645 body cap --> M42 macro tube --> helicoid --> 42-49mm ring --> 49mm +10dpt optic

cost in USD: $30 (cap) + $6 (macro tubes) + $60 (helicoid) + $4 (ring) + $10 (meniscus) = US$110

Next cheapest (and better) combo is:

camera, body cap, macro tube, helicoid --> 42-43mm ring --> Raynox DCR-250

and the cost: $30+$6+$60+$4 (as above) + $60 (Raynox) = US$160 or so.

Yes, either optic will project an image circle large enough for the 645 sensor. For focusing, remember that you need register + extension = focal length to reach infinity focus, and more extension for closer work. Play with the M42 macro tubes to get the right mix.

[slackercruster]

Yow. That is expensive. I take it you don't already have a P645 bellows? One problem with using such a bellows is its depth. It probably doesn't compress to less than 40mm. Add the P645 register of almost 71mm, and you won't be able to achieve infinity focus with anything shorter than a 115mm optic. There's a solution: an M42 focusing helicoid. See below.

First, we need a lens mount. My usual budget approach would be to find some screw-->P645 adapter -- but I don't see any inexpensive ones of any kind on eBay. Mount-reversal ring, plain macro tubes... nada, nothing, zilch.

So my next starting move would be to look for a trashed lens, and remove its mount. Do any other MF bayonets physically fit the P645 mount? Lacking such, another possible starting point is a P645 body cap, and I *do* see one of those on eBay right now for ~US$30.

Next step: turn an adapter or salvaged mount or body cap into an M42-P645 adapter. If an existing adapter has threads, step rings can be used to get to M42. Otherwise, an adapter or salvaged mount can have a wide-flange M42-PK adapter glued to it. The body cap is even simpler: cut a hole in it, into which an M42 male thread will fit. I would insert a shortest M42 macro tube section, thread it into the hole, then glue it in place.

Now we skip the expensive and too-fat bellows and go lean: an M42 16-35mm focusing helicoid, about US$60 shipped from Shanghai to USA. Thread that into the M42 female mount we've attached to the adapter or body cap. On the front of that, add a step-up ring to get from M42 to the optic's diameter.


I suggested either a +10dpt close-up meniscus (FL=100mm) or a +8dpt Raynox DCR-250 (FL=125mm). With my 49mm +10dpt optic (US$10 shipped) I use a 42-49mm step-up ring. With the Raynox (rear thread is 43mm) I use a 42-43mm step-up ring. The Raynox gives better images. The meniscus is cheaper.

The cheapest combo would thus be:

camera --> P645 body cap --> M42 macro tube --> helicoid --> 42-49mm ring --> 49mm +10dpt optic

cost in USD: $30 (cap) + $6 (macro tubes) + $60 (helicoid) + $4 (ring) + $10 (meniscus) = US$110

Next cheapest (and better) combo is:

camera, body cap, macro tube, helicoid --> 42-43mm ring --> Raynox DCR-250

and the cost: $30+$6+$60+$4 (as above) + $60 (Raynox) = US$160 or so.

Yes, either optic will project an image circle large enough for the 645 sensor. For focusing, remember that you need register + extension = focal length to reach infinity focus, and more extension for closer work. Play with the M42 macro tubes to get the right mix.

That is some complex stuff. Thanks for the roadmap on putting it togther.

The bellows, providing I can find a 645 set, may be OK for me. I only shoot protraits and close up with soft focus. So infinity is not that big a deal.

With the bodycap option. I wonder if I could hook up my 100mm T mount soft focus to a hole in the the body cap?

Where do you buy the single element optics you mention?

[RioRico]

That is some complex stuff. Thanks for the roadmap on putting it togther.

The biggest trick is finding or fabricating the right adapters. After that, it's just a matter of playing with rings and stuff until it all falls together. [/me looks warily at towering stack of rings & adapters teetering on the edge of /me desk]

The bellows, providing I can find a 645 set, may be OK for me. I only shoot protraits and close up with soft focus. So infinity is not that big a deal.

I mention infinity because it may not be so far from there to a portrait distance (1-2m) depending on the optics. The +10dpt (100mm) meniscus option cuts it a bit close. The +8dpt (125mm) Raynox approach gives a bit more leeway.

Also, even cheaper than either bellows or helicoid, just use M42 macro tubes to set a comfortable fixed-focus distance. I use some 75mm enlarger lenses at 1m or 1.5m fixed-focus for portraits, no problem.

With the bodycap option. I wonder if I could hook up my 100mm T mount soft focus to a hole in the the body cap?

Depending the thickness of the body cap, lens weight may be a limiting factor. I can put my helicoid, some tubes, and a small lens, on some thick caps. You'll have to see if your 100mm is light enough for stability.

If you get a thick enough cap, and carefully gouge a 42mm hole, you can screw both T2 and M42 threads into it (unglued). That may be your general-purpose adapter!

Where do you buy the single element optics you mention?

eBay. Besides the +1+2+3dpt or +1+2+4dpt sets, are also +10dpt and even +20dpt closeup offerings. I haven't had the nerve yet to try a +20, and I already have three +10s, woo woo. You want distorted as well as soft? Get a +10dpt with 49mm thread, and a 49-49mm thread-reversal ring, and mount the meniscus backwards. Edges get weird...

[slackercruster]

Thanks. I should not have trashed my enlarging lenses. Never knew they were useful with cameras until I came here.

[RioRico]

Extension (bellows, tubes, helicoid) allow stuffing all sorts of cheap optical materials onto the camera. Enlarger-projector-copy-xray-process-Fresnel-magnifier-scavenged-etc optics just await exploitation. Have fun!

[Yamanobori]

Soft focus lenses are just not out-of-focus. They are lenses with controlled spherical aberration, but yet can have high-resolving power. You can mount the Pentax 67 soft focus lens on a 645D.

[newarts]

These two adapters should get you in business - camera mount 645 - m39 visioflex $70 | m39- m42 step - up ring $4 |...& whatever else you need.... m42 will adapt to almost anything...

Fotodiox Leica Visoflex M39 Lens to Pentax 645n Adapter | eBay

Dave in Iowa

39mm-42mm M39 to M42 Lens mount Step Up Ring adapter | eBay

[yurihuta]

By way of the Pentax 67 (lens) - 645 (body) adapter, you can use the Pentax 67 120mm f/4 soft focus lens.