@apefos no worries!
16x9 makes a high quality 0.8x wide angle adapter that may serve as a good reference point:
http://16x9inc.com/shop/cart.php?m=product_detail&p=655
I have two examples of an earlier model 16x9 0.7x adapter, similar to this one, but with a 72mm filter thread:
http://www.amazon.com/16X9-Professional-Attachment-Panasonic-AG-DVX100A/dp/B000FLNWYK
The 16x9 0.7x adapter is very heavy but is by far the best wide angle adapter I've tried. There's very little blurring and aberration in the corners, but it needs a large matte box to shield it from flares. I know exactly what you mean by stopping down the main lens aperture to avoid blooming. I was able to use this adapter successfully with the Olympus 35-100mm f2.0 zoom, but only as open as f2.8.
@ LPowell
I checked your links and both these adapters are designed for small sensor camcorders. This is precisely the problem - nobody's really designed a WA adapter for large sensor cameras. The only one I know of is Panasonic's own adapter for the 14mm pancake, and it only works well with that lens. Maybe that's telling us something - a high quality, general purpose adapter for large format lenses may be impossible to build.
Developing is interesting because I do a set of tests pursuing some answer, so i rest a little bit and new ideas to do tests come into my mind. This way i am narrowing the possibilities.
I did new tests pursuing the squeeze factor and focus for GH2 and improving it for HV20.
I used the HV20 camcorder and the GH2 in different distances from the wall and using all possible zoom range. 14-42mm was used in GH2 kit lens and it can be used from 14 to 42mm. After assembling the final version of the adapter i will see if there is vignette in wide angle range. In HV20 i used from wide to 2.5x tele (the possible zoom range in hv20 is something about 43-100mm in full frame equivalent or 21-50mm in micro four thirds terms) I believe the camcorders who have a wider native lens will can do something about 30-100mm full frame equivalent or 15-50mm in m43 terms)
there are chances focus works from 0.7m to infinite allowing a face closeup. But focus is still the unanswered question which will determine the project success or shutdown. I do not have the final word yet. I will know the answer after building it with the final design. I am trusting in optical glass properties and physics rules, but I confess I am worried about this.
A good news is i did lots of tests with different lenses power and math calculations to pursue the final design and it seems the best balanced optical formula for the achromatic adapter for GH2 emerged. So now I can pull the trigger in one achromatic desing without need to build lots of lenses again. This is great. Tomorrow i will let these tests mature and if i think they are ok next week i will go to optical lab to ask them to do the lenses.
Some lenses in the design are dificult to do grinding, so there are chances the optical lab cannot do them with the glasses avalilable in stock on the stores. I do not want to develop a product who uses glasses hard to find. i will know this when i go there.
Some considerations about which photo lenses can be used with the "in development" dslr anamorphic adapter:
every and all photo lenses that can focus to a minimum distance of 0.3m or 1 foot (0.3 meter / 30 centimeter) or below can be used. you just need to read the manufacturer specifications or read the printed information in the lens focus ring to know. Just pay attention sometimes the focus ring does not show 0.3m / 1 foot (or below), but the specifications say it, so reading specifications is the best way to know. Just type in google like this: Panasonic 25mm 1.4 Specifications and you will find the answer.
Almost all vintage manual focus photo lenses equal and below the 35mm focal length can do this. (17mm, 18mm, 20mm, 24mm, 28mm, 35mm)
Lots of M43 lenses can do this, check the fourthirds dot org website
the GH2 14-42mm kit lens can do this in all zoom range.
the manufacturer specifications of sony nex, canon and nikon APS 18-55mm kit lenses says they can do that. I tested the canon 18-55mm and it can do that. If you check sony nex, canon, nikon, sigma and other manufacturer websites you will find other lenses that can do this.
before screaming the following information will ruins the project, remember the lenses above allow you to do a face closeup and also shoot wide enough to show a room or group of people and this is enough to do a movie, a wedding and so on.
not so good news is the olympus 45mm 1.8 and all vintage photo lenses in 50mm focal length and above cannot be used, and using diopters will hurt image quality. It was not a dificult decision for me because image quality is the main goal and to get focus with these lenses decreases image quality a lot in the corners. but dont worry there are solutions, keep reading:
so if you want 50mm focal length the solution will be to use the GH2 14-42mm kit lens in 42mm zoom position or to use APS 18-55mm kit lenses, (the nikon allow to adjust the diafragm). Also use lenses called MICRO/MACRO can allow longer focal lengths because they can focus closer, maybe below 0.3m / 1 foot. there are micro/macro photo lenses in 55mm and 60mm range and also in 90mm 100mm 105mm range. before buy them check if they can focus 0.3m / 1 foot or below reading the manufacturer specifications or looking at the information printed in lens focus ring.
I am thinking about to do a list of lenses after finishing tests if i realise the adapter works. I can list the lenses i did tests and a separate list of lenses i read specifications.
Next week I will try my best to solve the focus problems and if I can do it i will build the final version. My last experimentations narrowed the possibilities and i have the first version of the final desing ready to do. Also i need to know if the optical lab can grind the available glass to do the lenses i designed without need to search for larger and hard to find glass.
I did some tests with the nikon 50mm 1.4 lens. this lens has a similar minimum focus distance of olympus 45mm 1.8 , In general the 45-50mm range have a minimum focus distance about 0.45m to 0.6m
But this would need to be a second adapter, let me explain why:
To get focus with these lenses the power in the adapter lenses would need to increase a lot and the corners would get very soft. there are some curves in glass that allow to minimize this issue, also there are aspherical, low dispersion and high index glasses to help it. But there is another point: using more powerful lenses in the adapter it would increase the focal length of the 50mm prime lenses a little (i still dont know exactly how much) And to use this same adapter with wide angle lenses would not be good because it would increase their focal length and maybe they would not be wide anymore.
So the best balance would be two adapters, one for lenses with 0.3 meter minimum focus distance and other for lenses with 0.6 meter or even 1 meter minimum focus distance.
So it would be a good idea to develop a second anamorphic adapter designed for lenses from 45mm to 58mm, the fast vintage prime lens range which can be found for inexpensive prices. and if this range could be increased for the 85mm lens it would be better.
first adapter for: 14-42mm or 18-55mm kit lenses or primes from 14 to 35mm second adapter for: primes and zooms from 45mm to 58mm or from 45mm to 85mm
@ apefos
How about using an extension tube to get a 50mm lens to focus closer? That way there's no additional glass required.
Thanks for the tip. It works, tested it right now.
If the adapter works I can determine the exact length of the spacer ring (extension tube) for all the lenses: 50mm, 85mm 105mm 135mm
But there is a problem: I do not have resources to manufacture extension tubes with male and female bayonet mounts. and each lens brand and each focal length will need a custom spacer with its own bayonet mounts. Maybe we can use aluminium macro extension tubes sold on ebay and remove some rings just to get the male and female mounts, do a precise machine cut and weld them together in the correct length.
Do you know that feeling: Oh God! Why did I not think about this before!
I just hope i dont die as Joseph Petzval...
http://en.wikipedia.org/wiki/Camera_lens#The_Petzval_Portrait_lens
But there is a problem: I do not have resources to manufacture extension tubes with male and female bayonet mounts. and each lens brand and each focal length will need a custom spacer with its own bayonet mounts. Maybe we can use aluminium macro extension tubes sold on ebay and remove some rings just to get the male and female mounts, do a precise machine cut and weld them together in the correct length.
Cant you use an M42 heliciod extension tube like they sell on ebay? Then all folks need is a M42 to XXX camera adapter
I did take a look on it. The helicoid is a good solution. We would need to put the M42toM43 helicoid in the GH2 body and put the Nikon-M42 (or other brand) conversion adapter in front of it. The problem is i did not found conversion adapter from other brand lenses to female body M42 thread. Also the helicoid extension range need to be measured in combination with the conversion adapter (if it exists) to find the final extension size to see if it would work.
I found the extension tube (spacer size) to be inserted between the rear of nikon lens and the front of nikon-m43 adapter is someting between 7mm to 10mm length. And I believe this will be the same for all photo lenses from 50mm to 135mm. (needs tests to confirm). I will know this better when the adapter reach the final optical system (if it works!)
Both adapters projects are going on, camcorder and dslr. I did not stop developing the GH2/dslr adapter. The diy virus do not let me stop.
I had another meeting in the optical lab today early morning, they will try to do grinding glass for the new design I found this weekend. They almost gave up due to grinding the cilindrical lens takes too much time and they have other clients waiting. I beg them to do and offered more money to it. They said they will do at least the first one and they will decide to go on or they will point me to another lab. I just hope glass breaking do not became an issue which would make them to give up.
I am a little afraid I am boring people because I am talking too much and no results yet. But this topic is working as report that helps me not give up.
I hope I come with good news in a few days.
Be sure nobody is bored here. ;) With GH3 lack of multi aspect sensor anything that makes it possible to get a wider view becomes even more interesting.
Let the virus ride you. GL!
Man, I sure hope you can do it! Ever thought about a kickstarter-project? You know, the one where you can sell them in advance to cover your development costs? :) I would LOVE Anamorphic finally done RIGHT for dslrs. :)
@Meierhans medicine has no cure for virus yet!
@fatpig lessons learned from 35mm adapter times: just sell what is ready to ship.
I will use the plastic bodies and glasses to build and sell wide angle adapters for small camcorders because it is a tested and aproved product and i already sold some units and buyers liked it. this way i will recover the money i spent in this project
final answer is: i got the squeeze but i could not get focus, maybe using a positive cilindrical diopter instead of a spherical diopter will allow focus, but the negative lens needs to be far away from camera lens to get the squezee, because squeeze does not work when cilindrical lens is near the camera, so the glass needs to be large and i cant get large glasses in stores here and the optical labs just works with small and midsize glasses. when the positive cilindrical lens is near the camera it works as a cilindrical diopter and there is no squeeze, so using it in combination with a more powerfull cilindrical negative lens a little far away from camera lens and balancing its powers will allow focus and squeeze. but no more money to go on and no large glass to work with. sorry, project shutdown.
Unfortunate.
it is possible to make with big and small glass just very messy and not as cheap as you thought. the other issue is wastage cutting error is worse in anamorphics so you end up buying optics that are defective it took me over 2 years and i am still working on a lens. my belief is if you cannot beat or at least match a optex or century then it is pointless. the other disconnect in peoples brains is the belief that this could cost a 100 dollars.
the argument is simple old anamorphics like proskar or a sankor on ebay go for 80-250 usd in auctions a new lens has to be better than the competition if it is not you have to sell for less than 150 dollars. because people will want cheap and better. the old stuff is cheap and good quality. buying single element optics can be expensive double element is sometimes stupid money.
Good news: I got focus and squeeze using two cilindrical lenses, but it vignettes due to glass is not large enough, my theory from previous post is correct, the anamorphic adapter needs to be made with a cilindrical diopter (positive in the same orientation or negative 90 degree rotated). the cilindrical diopter correct focus and its position is close to camera lens, the negative cilindrical does squeeze and its position is far from camera lens, because squeeze increases as you far the cilindrical negative. I will share the optical design because i do not have resourses to go on and if another manufacturer wants to go on can use my optical design as a start point to develop the anamorphic adapter. the power of diopter and squeeze cilindrical lenses and the distance needs to be balanced to get focus and desired squeeze.
Also in the design if flat side on lens get no good IQ in corners, can use periscopic curves or meniscus curves to improve image quality in cornes,
the result: do not judge image quality, its just to show i got squeeze and focus. The project is shutdown, i do not have resources, time and money to go on. But my mission is done, i proved it is possible to do, but it is a task for big manufacturers.
@slrmagic take a look
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