Yes I'm afraid I have another adaptor.

So I played around with my Ed35 some more. This time I used better lighting and all that jazz. I exported to dvd and watched it on my big sony video monitor... the chromatic aberration is pretty nasty. It looks okay in FCP and as a compressed .mov file because of the small resolution. Once on a DVD and a large screen though.. the aberration is hard to miss. Mostly reds and blues. Some violet.

Here is a quick clip of some of the test shots. The girl was just reading random lines for us. There is no sound.

http://snodart.com/snodpublic/lines.mov

I am using a 58mm +4 and a 72mm +10.

So here is my question:

Couldn't this little guy be used in place of the +4 I have now?

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=77545&is=REG&addedTroughType=search

Yes, yes, I know the price is $200. Just humor me.

This should lessen the chromatic aberration a great deal correct? I understand that it is not an APOchromatic lense, but I can't seem to find one of those.

One last question:

(I am no optics guy BTW) Would the chromatic aberration be less/more depending on how exact the +4 and +10 are lined up with each other. The +10 is threaded between the DVX and the mount, but the +4 is held in place with set screws (as in Ed's design). Would it make any difference if the +4 was off just a bit and not exactly parallel with the +10?

I don't see myself spending the $200 for the achromatic diopter (out of stock anyway), but the chromatic abberation is just too noticeable on a big screen. I'm not sure what to do...
 
I don't think the parallel alignment would matter much, although the distances between the two may. I'm know optics guy either, but Quyen Le has mentioned that the placement of your achromat is important.

As an alternative to the Century achromat, you might try looking for a Canon 250D achromatic lens. These come in 52mm and 58mm sizes (those are the sizes on Canon's site). They sell for $120 and $130 (depending on size) on Canon's website, but you can get them for about $80 if you look around. I'm going to try one of these when I get my focusing screen in. I've ordered a generic achromatic lens (no filter threads, just the lens) from eBay to play around with the concept. I know what you mean about the chromatic aberrations. :( Really annoying.
 
By the time you guys finish testing "all other..." achromatic lenses, the old saying :
"you gat what you pay for" will be again proven to be right. Spend $ 80 here and $130 there only to come to the conclusion that $209 is the right answer to chromatic and other distortions. I have three of them (Century) for I walk my talk.
(not using any of them since I still don't have any camera to require them), but for testing, they are the only choice -to me-.
BTW. On the HVX I had for a few hours, I got a good image both ways: with and without achromatic lens. The pics at the bottom of this page:
http://dandiaconu.com/gallery/album51
are WITHOUT an achromatic lens. Like I said, it worked just as well WITH. I might have rolled some tape and have the image WITH as well (just a matter of going through footage and identifying it)
In the beginning, when there was nothing (to compare with) the simple shallow DOF got many people excited and dreaming....... now a day, only quality survives. It took over one year....
 
Optosigma makes Achromats. I *think* you could substitute the 50mm diameter with a focal length of 100mm for the +10, but it sells for $126.

I'm not sure on the math, but they also sell a 150mm fl lens that may work for both the +10 and the +4 for $116.

There is another thread for achromats in the DIY section where the math is explained.

I'm still waiting on my ED35 parts, so I don't have a platform to test them out.

-J

http://www.optosigma.com/miva/merch...ode=pg51-54&Category_Code=Achromatic+Doublets
 
I'm sure the Century lens is an incredibly high quality lens. I don't doubt that at all. For most of us making these things on a budget though, if we can get by with an $80 lens (which, from a 'below-the-poverty-line' standpoint is rather cheap) then why not? Cutting the chromatic aberration is the goal, and if an $80 lens will do it as well as a $209 lens then why not save $120? Sorry, not trying to be argumentative, I'm just keeping this all in context of the thread topic. This is all about building a quality adapter as cheaply as possible.

Also, for those of you not familiar with chromatic aberration there is a good example of it on the res charts on the page that dan linked to. Just look at the res chart in the bottom right hand corner of the page. If you look at the bluish fringe on the edge of the lines you'll understand what chromatic aberration is.
 
dan said:
By the time you guys finish testing "all other..." achromatic lenses, the old saying :
"you gat what you pay for" will be again proven to be right. Spend $ 80 here and $130 there only to come to the conclusion that $209 is the right answer to chromatic and other distortions. I have three of them (Century) for I walk my talk.
(not using any of them since I still don't have any camera to require them), but for testing, they are the only choice -to me-.
BTW. On the HVX I had for a few hours, I got a good image both ways: with and without achromatic lens. The pics at the bottom of this page:
http://dandiaconu.com/gallery/album51
are WITHOUT an achromatic lens. Like I said, it worked just as well WITH. I might have rolled some tape and have the image WITH as well (just a matter of going through footage and identifying it)
In the beginning, when there was nothing (to compare with) the simple shallow DOF got many people excited and dreaming....... now a day, only quality survives. It took over one year....
Click to expand...

Dan, I'm not exactly sure what you are saying. I'm not being rude, I would seriously like to know what you are saying.
 
Moochy, what exactly is the problem with the Thorlabs stuff? Is it not as fine a grit as the D screen, is there a lot of light loss? I'm running out of alternatives for the D screen (wax is not an option) and the Thorlabs stuff seemed like the best bet.
 
I'm curious about this as well, particularly how the thorlabs 1500 grit diffuser compares with the Optosigma 1500 grit diffuser...
 
1500 git is pretty grainy. The grit of my Go35 Standard glass is smaller than one quarter that size.
 
Last edited:
Yes. You'll really see it in blown out areas, or in panning across varrying areas of contrast. Grit size always matters.

According to this link, 1,500 grit is around 12-14 micron. 5, 3 and even smaller micron grit sizes are out there if you look for them.

I'll save you some trouble and let you know nothing below 1 micron seems to work, however.
 
I couldn't let this illustrious thread go a full day without a single post. :D How absurd. I've got my parts in with the exception of the GG. I am going to try one from one of our fellow DVXers here and see how that works out. Trying to get this Nikon screens is like "trying to film yourself".
 
ovjamaica said:
I couldn't let this illustrious thread go a full day without a single post. :D How absurd. I've got my parts in with the exception of the GG. I am going to try one from one of our fellow DVXers here and see how that works out. Trying to get this Nikon screens is like "trying to film yourself".
Click to expand...

I agree, where is everyone?? I've ordered a +10 macro from America, but it will take a while to arrive here...no idea how long to be exact. I've also ordered a +10 achromat , i'll be able to try both out and test the difference between the macro's. Like Edweirdo said, staking macro's is a bad idea, too much blurring around the edges.
 
Well now there are other things to life other than 35mm DIY :) Hopefully we are all out shooting as well...

Ovjamaica- true those D screens are sneaky but they are out there. Until then we continue to research replacements. Dumb B&H told me 3-4 days to get my Linhof screen in and still nothing, yet they will not let you cancel an order for what they consider a "specialty item". I could have had it shipped from Germany by now!

bklyndv: would you be able to post any pics from your Go35 with a D screen/your GG comparison, as you say it gives better results? Or would you consider lending me one of your GG screens so that I may place it in my adapter and do a side by side? With all the PMs I am getting, people are wanting to build this thing but the D screen is a brick wall.

In other news: I am currently revising my design slightly as I have discovered something last weekend that may take the Asian macro out of the equation and hopefully remove any chromatic abberation. And yes it has to do with achromats: Precision, I cant wait for your findings and Dan, thanks for the wisdom! :)

This slight revision will not affect the desing in any MAJOR way that is- but you may need to buy another $3 piece of PVC (for those who have built this already). I will be ordering the parts tomorrow, and hope to have more info on this next week.
 
You must log in or register to reply here.
Back
Top