[barondla]

Cobbled together a lens reversing ring by using a 6X7 reversing ring with 645 to 6x7 adapter. Unfortunately the DFA 645 lacks a mechanical aperture ring. Anyone make a ring for the lens mount that would allow dialing in different apertures?

Thanks,
barondla

[pacerr]

Experimenting with various lenses on the Q's with DIY extensions and adapters I found it satisfactory to employ opaque disks with fixed 'aperture holes' to explore DoF issues. No objective comparisons made relative to placement in the 'stack' but exposure was simple with TTL metering.

Interesting results when placing the aperture hole off center but didn't follow through with that variation or with multiple holes.

[MossyRocks]

washers or bushings are always a good choice

[Not a Number]

Somebody mentioned an adapter with aperture ring that could be used in one of the other many threads on this subject. Try the search function.

[johnha]

Can't help with the original question, but have you considered coupling lenses: Coupling lenses for extreme macro

Basically mount one lens 'normally' and reverse another on to the front (the focal lengths determine magnification). You would be able to control the aperture of the normal lens normally. You need a coupling ring to attach the lenses filter thread to filter thread.

[zapp]

Cobbled together a lens reversing ring by using a 6X7 reversing ring with 645 to 6x7 adapter. Unfortunately the DFA 645 lacks a mechanical aperture ring. Anyone make a ring for the lens mount that would allow dialing in different apertures?

Thanks,
barondla

What lens are you using in reverse. Somehow your question is lacking some information. Can you stop down the lens and just want to control the aperture from the camera? Controlling aperture on a 6x7 lens in reverse on a 645 camera... there will be no automatic adapter, no market.

[barondla]

Somebody mentioned an adapter with aperture ring that could be used in one of the other many threads on this subject. Try the search function.

Finally found it! Pentax made a 2 piece set. The Reversing Adapter that fit the 645 lens mount and the part asked for in the original post, the Reverse Attachment. The Reverse attachment fits the forward facing lens bayonet and has a control ring. Turning the ring moves the lens aperture lever allowing wide open to fully stopped down operation. Similar to the Q to PK adapter.

Thanks,
barondla

---------- Post added 04-09-20 at 01:08 AM ----------

What lens are you using in reverse. Somehow your question is lacking some information. Can you stop down the lens and just want to control the aperture from the camera? Controlling aperture on a 6x7 lens in reverse on a 645 camera... there will be no automatic adapter, no market.

I already had a Pentax 6x7 reversing ring with 67mm filter thread. Added a 645 to 6x7 adapter. This allows using the DFA645 55mm lens reversed. It's probably the worlds biggest reversing ring

Thanks,
barondla

---

Last edited by barondla; 04-08-2020 at 11:10 PM.

[kaseki]

Finally found it! Pentax made a 2 piece set. The Reversing Adapter that fit the 645 lens mount and the part asked for in the original post, the Reverse Attachment. The Reverse attachment fits the forward facing lens bayonet and has a control ring. Turning the ring moves the lens aperture lever allowing wide open to fully stopped down operation. Similar to the Q to PK adapter.

This "set" seems to be missing on the Pentax Accessory Reviews » Close-up and Magnification Accessories » Bellows, Extension Tubes, Etc. (Genuine Pentax) page. If it is not addressed somewhere else, please consider doing a review.

[barondla]

This "set" seems to be missing on the Pentax Accessory Reviews » Close-up and Magnification Accessories » Bellows, Extension Tubes, Etc. (Genuine Pentax) page. If it is not addressed somewhere else, please consider doing a review.

Unfortunately I don't own these accessories. Sorry.
Thanks,
barondla

[kaseki]

Ah, I misinterpreted your word "found." I have ordered a set from Japan to experiment with, so I guess it has to be me who has to write something meaningful (in the fullness of time).

[barondla]

Ah, I misinterpreted your word "found." I have ordered a set from Japan to experiment with, so I guess it has to be me who has to write something meaningful (in the fullness of time).

I look forward to your review and haven't ruled out picking up a set.
Thanks,
barondla

[barondla]

Here is an image taken with the 645Z and Pentax DFA645 55mm 2.8 reversed. My reversing ring was the cobbled together 6X7 reversing ring with a 645 to 6X7 adapter ring. This is probably a little thicker than the real Pentax 645 reverse adapter ring. So it might provide slightly higher magnification. The DFA has no aperture ring and I don't have the piece that bayonets onto the rear of the lens to allow setting the aperture manually. A wire was used to hold the lens aperture lever at a middle setting.

At first this lens appeared to have a hot spot in the middle, like often seen with certain lenses shooting infrared. Then I moved the lighting around and got two hot spots. Believe the bright solder joints are causing lens flare or these could be reflected off the sensor itself. The DFA lenses should have a coating to reduce sensor flare, but I'm guessing it is on the rear element, which isn't doing much good now located at the front. Will try different subjects to see if it's an every day problem. I'm happy with the sharoness.

Thanks,
barondla

[kaseki]

Ah, I misinterpreted your word "found." I have ordered a set from Japan to experiment with, so I guess it has to be me who has to write something meaningful (in the fullness of time).

Received the parts yesterday morning; this is the shortest time in my experience getting a camera part from Japan, and I do not anticipate surpassing that record in the future.

I will provide here aspects of a review as I get to them. Interested parties may wish to download from one of the Pentax manual sites, e.g., ManualsLib - Makes it easy to find manuals online!, the four-page "58mm Reverse Adapter 645/Reverse Attachment 645" manual, part no. 07031 ENG, dated 5/84. I will be writing as I am learning.

There are two components, one for each end of the lens assembly to be reversed. One part -- the reverse adapter -- attaches to the lens filter thread, the other -- the reverse attachment -- to the lens rear mounting flange. The reverse adapter allows the front of the lens to be connected to the camera mount or to extension tubes for greater magnification. The reverse attachment, while providing a thread for a filter at the front of the assembly (rear of the lens), has as its main purpose an interface with the aperture controls such that one can manually open the aperture for focusing, and then manually close it to the desired f/no for taking the image. The lens must not be in the A (automatic) mode for this to work.

With the lens reversed, no electrical contacts or mechanical controls are accessible to the camera. However, TTL functions of stopped-down metering (and I think also analog TTL flash for film cameras) should work. I am less confident about P-TTL on digital cameras. TBD. Flash lamp configurations that achieve one's goal when one is on top of an object to be highly magnified are another issue not addressed here.

It is important to note in this first tranch of information that this device is designed for 58mm filter thread lenses, such as the 75mm 2.8, and adapters will be needed for lenses with different filter threads. For example, the 120mm macro lens uses a 67mm filter thread. I believe the part needed is called a stepping ring, and I will have to order one.

kas

[RICHARD L.]

Another way to attain huge magnification ratios is using the 645 bellows unit. I don't have this piece of equipment for the 645Z but I used a Minolta bellows III for a number of years with my old Minolta film system with great succes. I followed grasshoppers during a summer and became proficient enough that I could photograph them handheld, something that would be impossible now with this large and cumbersome 645 camera set-up. Just my 2 cents ! You're quite innovative and fun to follow, Barondia my friend ... lol !

Regards,
Richard

PS I found a 645 automatic bellows on eBay selling for 240 $ US. It comes from Japan and seems in like-new condition.

[barondla]

Received the parts yesterday morning; this is the shortest time in my experience getting a camera part from Japan, and I do not anticipate surpassing that record in the future.

I will provide here aspects of a review as I get to them. Interested parties may wish to download from one of the Pentax manual sites, e.g., ManualsLib - Makes it easy to find manuals online!, the four-page "58mm Reverse Adapter 645/Reverse Attachment 645" manual, part no. 07031 ENG, dated 5/84. I will be writing as I am learning.

There are two components, one for each end of the lens assembly to be reversed. One part -- the reverse adapter -- attaches to the lens filter thread, the other -- the reverse attachment -- to the lens rear mounting flange. The reverse adapter allows the front of the lens to be connected to the camera mount or to extension tubes for greater magnification. The reverse attachment, while providing a thread for a filter at the front of the assembly (rear of the lens), has as its main purpose an interface with the aperture controls such that one can manually open the aperture for focusing, and then manually close it to the desired f/no for taking the image. The lens must not be in the A (automatic) mode for this to work.

With the lens reversed, no electrical contacts or mechanical controls are accessible to the camera. However, TTL functions of stopped-down metering (and I think also analog TTL flash for film cameras) should work. I am less confident about P-TTL on digital cameras. TBD. Flash lamp configurations that achieve one's goal when one is on top of an object to be highly magnified are another issue not addressed here.

It is important to note in this first tranch of information that this device is designed for 58mm filter thread lenses, such as the 75mm 2.8, and adapters will be needed for lenses with different filter threads. For example, the 120mm macro lens uses a 67mm filter thread. I believe the part needed is called a stepping ring, and I will have to order one.

kas

Wow, that is fast shipping. Besides the 75mm, what other lens are you going to reverse? Don't think the 120 macro will gain anything. Usually normal and wideangle lenses are reversed. The wider the lens, the greater the magnification.

I ran into a couple of interesting things. 1st, standard design lenses don't change focus when reversed since the mount is uncomnnected from the body. The DFA 55 internally focuses and focus changes when the lens ring is adjusted. 2nd, the internal focusing causes magnification to change some. I shot with rear element retarcted to protect the glass from bumps and flare. Wonder if changing rear element position would affect ultimate picture quality?

I'm using the 6X7 revesre adapter (with 645-6X7 adapter) the lens size is 67mm which natively fits the DFA 55, but wouldn't fit the 75mm without step down rings.

---------- Post added 04-14-20 at 09:50 PM ----------

Another way to attain huge magnification ratios is using the 645 bellows unit. I don't have this piece of equipment for the 645Z but I used a Minolta bellows III for a number of years with my old Minolta film system with great succes. I followed grasshoppers during a summer and became proficient enough that I could photograph them handheld, something that would be impossible now with this large and cumbersome 645 camera set-up. Just my 2 cents ! You're quite innovative and fun to follow, Barondia my friend ... lol !

Regards,
Richard

PS I found a 645 automatic bellows on eBay selling for 240 $ US. It comes from Japan and seems in like-new condition.

Thanks for the compliment Richard L. This is a hobby for most of us and should be fun! Are you going to get the 645 bellows? Doubt it could be used hand held, but I've been trying the 645 with A 120 macro and AF540 flash. It's possible for short durations.

Thanks,
barondla