DIY MIDFORMAT LENS ADAPTER Tests & Samples

[Ted Ramasola]

All,
I'm starting this new thread from the previous one, "DIY mini35 using mediumformat lens" Since I have significantly modified it and is now in testing stage.
I hope my posting this tests results, and eventually the DIY instructions, could help anyone, and me as well, who intends to take this route to improve on or make modification on this device.
There might be those who may find the results already fit for their needs and those who would say, not yet.

I promised the guys in my PLYWOOD SKATER THREAD this update so here it is.

"Version 2" of the DVX DOF-120 medium format lens adapter for the DVX.

Figure 1. The setup for the tests and the pic of the adapter on the dvx.


Figure 2.
Side by side grabs. W/o the adapter, w/80mm & w/ 45mm. Focus for this grabs is on the clock.


for the full images click on the links.(I suggest you put them on your timeline to view on your monitor, cnverted to jpg already)

Still life-no adapter

still life-80mm

still life-45mm

Figure 3. Resolution chart shots with the 80mm lens at f1.9 on the 80mm and f8 on the dvx iris.


link to video of this tests

Set up and resolution chart and GG when turned OFF 19.5mb

still life shots-rack focus & w/o the adapter 45.9mb

Were gonna change to a better close up filter solution, the island only got +3 and I stacked 3 and the diameter is only 55mm, I intend to fly to our capital city to get a better filter and also change to a better brushless motor.

So for now if anyones interested in this setup the version 1 contstruction photos on the previous thread still applies except that the tube for the magnifying lens is removed and the aluminum base plate shortened.

Credit where its due, Many Thanks to www.stickypod.com for allowing DVXUsers to post our files.

[Unix]

wow
that 45mm image looks great!!!
congrats
keep us posted
XD

[RoamingBobert]

Teddy, you mentioned changing to a different motor - is there a problem with the other one?
Also you talked about using frosted CDs as your ground glass - is there a reason you've chosen not to use actual ground glass?

I am excited about this project - I bought four medium format lenses yesterday for this purpose!

[Ted Ramasola]

RoamingBobert,

the current motor I'm using, comes from a cd kit, 12v and is for a DIY cd player. Its working fine because I underpowered it by either a 9v battery or 2pcs of 1.5 v AA batteries. The motor which i plan to replace it with is much smaller and lighter 5v brushless motor which i got from an old DVD Rom. its the cooling fan from the rear. It looks like the cooling fan of your power supply or pc only much smaller.
And it very quiet.

Regarding my choice of "ground glass".
First, actual glass is hard to spin DIY style. Most DIYers using glass went for the occilating or vibrating method. For me the, miniature mechanism of osccilating gg holders is too intricate and in the long run for me, hard to maintain.

I cant go for static because I cant find a very fine ground glass. I have a lot of focusing screens lying around from my grandfather's bauch and lomb large format view camera(yeah they make cameras before, not just raybans), speedgraphics4x5 to the focusing screens of our RB67s. But theyre too big in grain.

The frosted cds, once spun, produce smooth 'acceptable' images. Check my samples.

[Ted Ramasola]

heres a chart done with 80mm, did this a while ago.
I'll label this test chart jan08.

I've managed to "push back" the softness on the sides to the fringes. Its still pronounced at the corners. This is "negligble" if I letterbox my shot. But thats just me. Theres "a little" CA on contrast areas near the vertical grayscales.



Once I get this to MY acceptable and MY usable level, I'll be using this on a promotional AVP I'll be doing in the coming weeks.

[RoamingBobert]

Ted,
is this latest pic after you changed the close up filter or before?

Thanks for the reply to the other questions, I really like the look of the images so far. I wanted to get into your head a little and understand your decision making process!

[engr]

now thaz SHARING!! Thanks!!

[Ted Ramasola]

RoamingBobert

This is still using +3(x3) but i've changed the distance to the "GG". its now 3/4 of an inch gap between close up and GG. I'm assuming at this stage that if i have a wider diameter close up and bigger power, I 'might' be able get 'greatly minimize' or hopefully eliminate the vignette effect and softening at the corners.

Can anybody correct me on this?

Thanks in advance

Ted

[Ted Ramasola]

All,

Ive done a series of "real world" tests today. Still life, people, etc.
Done with 80mm rb645 lens.



Not Bad for a plastic frosted CD ground glass that came free with a DVD spindle!

If anyone likes what he sees or has a means to improve on this, please say so, so I'll post the diagrams and construction plans for this DIY device, -FREE!

If anyone can share insights on what I'm doing wrong please help me improve this.

Thanks.

Heres a link to the videos, its full res MSDV codec video showing those shown above so you guys can assess the sharpness (or accept the tradeoff softness) and to check for grain etc.

Testshot-1 Jan09

Test shot-2 Jan09

[RoamingBobert]

Teddy,
I noticed that you used two rear lens caps to mount your lenses to your case. Have these been secure or have you had any problems with them? I have a couple of old medium format cameras on the way and I was thinking about canabolizing them and using the lens mounts there. Is this something you tried and dismissed?