Pham Minh Son
Offline
• • •
Upload & Sell: Off
|
 p.1 #5 · Preparing for 1Ds III - Sharp Lenses + Adapters | |
raul jarquin wrote:
Hello, I need a lot of advice so please forgive my long post. I pre-ordered a Canon 1Ds3 hoping to switch from medium format film (Rollei 6008) to digital at a quality level that hopefully will approach my standard C-prints for 20"x20" landscape work. I imagine many other people are planning the same so hopefully your answerers to my questions will help others.
My medium format systems right now are the Rollei 6008, Rolleiflex Hy6, Rolleiflex TLR (FT, FW, FX) and Contax 645 systems. Among these 3 systems I am able to extend my range of applications.
From looking at my initial results for both the Contax-Zeiss and the Zeiss ZF lenses the only conclusions I could make with some certainty were that:
- At infinity, the lenses were not giving me the critical edge-to-edge results I wanted until f8 or higher.
With the perfectly calibrated lens and the right adapter thickness, especially with those lens with floating elements (the non floating element lens can be readjust yourself since the formula for these lens are not as complicated due to dependent lens integration), the performance of these optics will deliver high quality. Some of the sharpest lens you will find at wide open f stops are: Distagon T* 2.8/21 C/Y (Contax/Yashica Mount), Planar T* 1.2/55 C/Y, Planar T* 1.2/85 C/Y. These lens pound for pound are the top resolution lens in its class.
- The Zeiss ZF lenses while slightly sharper than their corresponding Contax counterparts, will generally show more chromatic aberrations.
With the proper adapter thickness, even the Planar T* 1.2/85 C/Y lens at wide open has great chromatic aberration control and high micro/macro contrast and actuance (resolution). Do not forget that the solution of the adpater thickness for the Canon adapter is solved but the Nikkor mount adapter is not determined yet. Therefore, it has been assumed that the Nikon mount adapter thickness is not a problem but we do not know until we can test the adapter in those lens. Therefore, it may be premature to make the absolute conclusion of chromatic aberration on the ZF lens. However, Zeiss has made changes in their optic designs for these lens and therefore a compromise could exists.
I suspect that both of the above results can be attributed to adapter issues so please do not make any conclusions from the above statement. What is very clear to me is that if you are going to get non-canon lenses to improve image quality you need to pay attention to the adapter to lens combination, specially, when taking images at near infinity or with large apertures.
Yes, adapter thickness is essential to optimize the lens performance in their original designs. In addition to infinity or near infinity, my tests have shown that if the lens cannot reached infinity with the adapter, its performance is greatly reduced whether at infinity or in the closest focusing distance of the lens.
The questions I have are:
1. Are the Pham Minh Son adapters with various thicknesses to match different Contax lenses still available? I could not open the website that is referenced on some posts related to his adapters at http://www.AdapterSolutions.com
I still have some thinner adapters and the thicker one come by once in a while in the forum sale. I no longer make them but willing to make another run for the forum if enough people are interested. There are still adapters floating around in the forum so you can pick up a use one. In addition to being at different thickness to match up every C/Y lens, these adapters fit the tightest in the market in order to prevent lateral shift from the center of the lens. If anyone bought one of these adapters and need a tool to get them on and off their lens and the seller no longer has the removing kit, email me and I will support you ([email protected]). Since I am not completely moved and with too may matters at hands, the website server will not be up and running until the next year.
2. Is the adapter thickness particularly problematic with the 5D model and I can expect a better experience with a 1Ds3 (or even an older 1Ds2) ?
Yes, the 5D mirror has the plastic holder stage coming out more so than the metal mirror holding stage of the 1 series Canon DSLR cameras. In addition, the mirror of the 5D is not attached well onto the stage and could lead to potential problem when cutting the mirror.
3. All of my current lenses mount correctly with the various adapters (see exception below) but if I were to use a Pham Minh Son adapter, will I need to make body or lens modifications on lenses longer than the 21/2.8?
Not every lens require the mirror to be modified, the Distagon T* 2.8/21 with the right adapter for it will not require the mirror to be cut. However, there is one more issue that must be cleared, beside the mirror cut the mirror housing also must be slightly modified in order to allow all of the high end Carl Zeiss C/Y mount lens to freely move the aperature ring when stopping down. The lens that has the most problem is the Distagon T* 3.5/15 which require the thinnest adapter ever to get to infinity focus. However, if you are willing to make the lens work it is a joy to use this lens. Becareful though, this lens must be in calibration to get the best out of it. Today, I know Tom has the best copy of this lens that I have tested and it comes with the proper adapter. In addition, if the mirror is modified, then all of the great and difficult Leica R lens can also finally be used in the camera. Thus, this is an extra benefit.
4. Is there a place that will calibrate older Contax Zeiss lenses to their original specs? if so what is the usual fee?
Only Zeiss in Germany can calibrate the difficult one and the fee varies depending on what needs to be done. It is worth it if you love the lens and want to keep them. I have done this with almost all of my lens from 135 mm to medium format systems.
I am testing a bunch of lenses but I intend to keep only a handfull of them that make sense for the type of work I do and the results I need. I have from Contax the 21/2.8, 28/2.8, 50/1.4, 60/2.8 1:1, 85/1.4, 35-70/3.4. I also have the 28/2.0 Hollywood but I have not tested this lens because I do not think it will clear the mirror on my 5D. From Zeiss ZF I have 25/2.8, 50/1.4, 35/2.0, 100/2.0 and I have preordered the 28/2.0.
I would wait to see the new Zeiss Distagon T* 2.0/28 and how it will compare to the Hollywood.
By the way, I intend to keep my Rollei 600x gear to continue to have access to film based photography and I hope that one day I can use my Rollei lenses on a true square digital back with no cropping.
Thank you for your feedback
I also shoot film with my medium format systems. For example, I traveled with my new Rolleiflex TLR FT and I can shoot this system at 1/15 second hand held and with the pistol grip I can go down to 1/8s. The negatives and slides come back from this system are very high quality and give you a different looks from the digital back. This system can also have the true high flash sync up to 1/500 s when it is needed.
I have made 4 of the Contax 645 auto bellows to use with 4x5 image circle lens for tilt, swing, and shift in the medium format system. I will soon add the Leica R, Leica Visoflex, Canon EF, Nikkor and Sigma SA mounts to work on this very auto bellow system so that macro, product, flowers, and stitching applications are facilitated regardless of platforms.
-Son
Edited by Pham Minh Son on Oct 31, 2007 at 04:43 PM GMT (Reason: for clarity)
|
