Introducing one of the newest adapters, the BJ35. The BJ35 is a static 35mm adapter. The ground glass is custom ground utilizing the PCX (Plano Convex) lens found in Nikon F3 focusing screens (ground glass can be purchased also). This allows the ground glass to also be a condensor which helps solve hotspotting and vignetting issues. The glass is ground with a fine 5 micron grit which produces suitable results for a static adapter. This adapter also comes with a high quality achromat and a user guide., not to mention a 7 day satisfaction guarantee and free shipping. There are also options for various lens mounts.
I've finally got around to cleaning up the look of this site. I plan on adjusting a few things over the next few days. Hope everyone enjoys the nice clean look of the site.
*Update This is not a 35mm adapter in terms of the adapters discussed on this site. It actually allows attachment of lens extensions to produce macro footage (which has a shallow depth of field).
The following footage I came accross comes from the Showtime 35mm adapter out of Taiwan. Granted all the footage are macro. Unfortunantly the site is not in English, so i am unable to translate. (If anyone want to translate this site it would be greatly appreciated as this is some of the better adapter footage I have seen.)
Many might know that the SGpro Spinning 35mm Adapter is an extremely high rated alternative to the very pricy Redrock Micro M2 adapter. An many would argue the image quality produced by the SGpro is superior to that of the M2. Regardless, this post is to announce the upcoming SGblade. The SGBlade is in addition to the Shoot35 product line and not a replacement of the SGpro. The specs sound great and the unit looks top notch.
Pricing and availability are yet to be released, however this is definantly a product to keep your eye on.
SGblade specs:
SGblade is a spinning design offering a smaller ground glass
Choice of GG type upon order. -GG Choice1: Real glass disk, resulting in low light loss and grainless. -GG choice2: Current SGpro element - better bokeh (the famous SGpro look/aesthetic).
Special coatings on every optical surface (including GG) in order to improve light loss.
Custom CNC'ed curved enclosure, much smaller than current SGpro.
Film plane 'tape measure' hook.
Internal power
Adjustable GG speed.
All mounts having collimation 'on the fly'
Convert lens mounts to stainless steel.
Improved rods support system (replace shims with sliding assembly) with 'shoot35 red' anodized thumbscrews.
X/Y adjustment for the flip module section.
Compact 'non flip' Blade (for 1/4 chip cams)
'non flip' Blade (for 1/3 chip or bigger cams)
The main Blade unit (without lens mount or cam connection)
The Blade 'flipped'
For more information and updates on the SGBlade please visit Shoot35 community.
Today I will provide insight on grinding your own glass for your adapter. There are a few options to consider when grinding your own glass such as glass type and desired grain (determined by grit).
Why grind your own? You could purchase a Canon EE-A EE-S focusing screen and achieve great results, however these screens are extremely fragile and can get costly to replace. DIY ground glass can a budget friendly alternative and can be washed with soap and water and not be harmed. One advantage the aforementioned focusing screens have is a built in condenser (Fresnel lens) that reduces vignetting and light loss, however there are ways to compensate for this with your own ground glass which I will get into.
What glass should you use? A lot of people use cheap microscope slides which work fine, however you will have hotspotting and vignetting if a separate condensor lens is not installed. An alternative that does not require a separate lens is to grind the plano (flat) side of a plano-convex lens. Justin Snodgrass(snodart.com) suggests using the plano-convex lens from a Nikon F3 series focusing screen***. This is a good option for size and quality.
***Update Nikon F4 and F5 focusing screens also utilize the same quality PCX glass
What grit do you use? Aluminum Oxide grit works well and comes in different flavors (sizes in microns). The size grit you use comes down to adapter type and personal preference. For static adapters I would suggest a grit size of 5 microns. For vibrating or spinning adapters it is pretty open to preference. Aluminum Oxide grit can be purchase from GotGrit.com.
How do you grind it? Grinding is a pretty simple task.
First you will need a larger piece of glass to grind on. You could use glass from an old picture frame or any glass, just be careful the glass is not too thin as it could crack.
Next put a bit of grit in the center of this glass
Mix water with the grit and achieve a light pasty consistency
Then place the glass (for a PCX glass place flat side down) on top of the grit and pull a continuous figure 8 pattern for 10-15 minutes rinsing the glass frequently
That is it. Of course, like anything, it probably sounds easier than it is. However with a little practice you can achieve quality ground glass that provides you control and is durable and cheaper. Good luck!
I posted a while back that there was a new maker of GG holders. Seems like he makes his own ground glass and full adapter solution as well. Introducing the GT35pro.
Ground Glass (focusing screen) Holder The kit comes in a set. The gg holder (including the metal legs, the vibrating motor and 2 ground glass of your choice. All the parts have been tested over and over again to make sure that the vmotor vibrates the focusing screen correctly.
Ground Glass (focusing Screen) - 5 micron grind USD$20 up to 40mm x 30mm size - 9 micron grind USD$15 up to 40mm x 30mm size - 20 micron grind USD$12 up to 40mm x 30mm size These glass can be touched washed and cleaned, unlike those canon EE-A or EE-S screens that spoils after you touch it.
GT35pro Vibrating 35mm adapter The Price of the adapter without achromat and lens is $260.
***Update 9/8/08*** I have a quick correction that I plan to follow up with a new post on condensors, specifically using a PCX lens as a condenser. I mentioned below that the PCX condenser spreads light...this is not true. the PCX condenser actually converges light on it's own, however, it can be used to counter the diverging light coming from a 35mm lens and produce and even consistant light stream...I will have a new post on this topic soon. ******
Actually I should say “Spreading Some Light”. One of the least talked about elements of an adapter is a condenser. A condenser is most commonly a plano-convex lens (PCX) and basically spreads light. You would want to use one in you adapter to help eliminate the center hotspot and reduce vignetting.
Placement The condenser would typically go between your 35mm lens and your ground glass (focusing screen). In essence it will take the incoming light from the 35mm lens and widen it to a larger area on you ground glass resulting in more light and less vignette.
Is a condenser necessary Most would say a condenser is an optional element to an adapter, but I personally feel the benefits from a good condenser are too great to ignore. Overall image quality is much improved and PCX lenses are inexpensive.
When to use a condenser I would recommend a condenser if your footage suffers from vignetting forcing you to zoom in extra on your ground glass. Also, if you are using custom made ground glass, wax screens, or other (example: I am utilizing a focusing screen found in the LCD of an old cell phone) I would say you will most likely want to use a condenser.
Canon EE-A/EE-S screens got you covered If you are using a Canon EE-A/EE-S focusing screen then you already have a condenser. The EE screens have a fresnal lens attached which is actually a condenser.
