Horizon Perfekt
From Silvergrain Labs
Horizon Perfekt is a panoramic camera made by Zenit (a Russian optics manufacturer) featuring a swing lens mechanism, using regular 35mm film. This camera is identical to Horizon S3 U-500 except for the exterior printing and perhaps the kit content, and similar to S3 Pro and S3 Sport. S3 Pro and S3 Sport differ from S3 U-500 in shutter speed range. S3 Pro features slow shutter speed down to one full second, but according to a camera retailer in Moscow this model has been discontinued.
There is also Horizon Kompakt, which is a stripped down version of this camera, limited in terms of shutter speed and aperture control. In Kompakt, the film advance and shutter charging are not linked, so there is no provision to prevent double exposure if you are not very careful.
Most websites describing this camera are written from toy camera user's viewpoint. While this camera definitely appeals to the toy camera cult, this article tries to discuss this camera more deeply.
Contents |
Images made with Horizon Perfekt
The following images were taken with a Horizon Perfekt, modified with the procedure described below, to bring foreground objects into sharp focus. These images are from very first roll of film that went through my camera, so it shows some imperfection of my modification process, but don't worry, I figured that part better and will describe how to do it right in the modification part.
Specification
| Major specifications of Horizon Perfekt | |
|---|---|
| Image size | 24 x 58 mm |
| Image angle of view | 120 degrees horizontal, 45 degrees vertical |
| Viewfinder angle of view | 110 x 44 degrees |
| Lens | MC Arsat 28mm f/2.8 on a swing (rotating) platform |
| Focusing | fixed; probably focused at about 10 meter |
| Film | 35mm film |
| Image size | 24x58mm |
| Aperture ratio | f/2.8, 5.6, f/8, f/11, f/16 |
| Shutter speeds | 1/2, 1/4, 1/8 (slow swing); 1/60, 1/125, 1/250, 1/500 (fast swing) |
| Exterior | ABS plastic |
| Size | 152 x 115 x 79 (mm) |
| Weight | 750g |
| Battery | No electric circits in this camera |
The film is advanced manually by the lever. Film advance also charges the shutter. This camera does not have provision for multiple exposures. The lens is fairly small for 28mm f/2.8 lens, and it is mounted on a platform that rotates during exposure, the platform which is driven by a clockwork motor. There is no standard filter thread, but the camera comes with a UV filter, a ND filter (1 stop) and green-yellow filter.
The film plane is in arc shape to match with the rotating axis of the lens. Therefore, the film feeding path is rather complicated and loading this camera is not as easy as regular SLR or rangefinder bodies. However, this swing panorama is something uniquely film because film is flexible and bendable, while current image sensor chips used in digital cameras are not. Horizon panoramic camera is an ideal tool for those who want to explore something that cannot be done digitally.
This camera exposes only a narrow vertical strip at any moment, and this strip sweeps on the film surface from left to right (facing emulsion side) as the lens platform swings. The exposure time is determined by the width of this strip, controlled by the slit shutter. Therefore, the lens only needs to cover about 45 degrees in the image circle of about 30 mm. There are many excellent designs for lens of this specification and indeed the lens on this camera takes images of very high contrast and sharpness, certainly in the same league as more serious equipment. However, the performance of this excellent lens is not fully delivered due to disappointingly high level of internal reflection in the camera, especially at the edges of the slit shutter in the film chamber, making annoying tails around bright spots in high contrast scene (see Reducing Internal Reflection section below for details).
The camera has a spirit level on top, which is viewable inside the viewfinder. The camera is equipped with a 1/4 inch tripod screw and a proprietary screw to mount a holding handle (to hold camera without the risk of photographing the hand).
Known problems, Complaints and Feature wish list
Focusing distance
This camera has one major problem in my opinion. The lens is most likely focused at 9.9m distance (this fact is not published but consistent with their depth of field guideline). This 9.9m is the hyperfocal distance for 28mm at f/2.8 with circle of confusion of 0.028mm. (See Note on circle of confusion below.) While this may be ideal for people who shoots nothing but boring landscape, this is a terrible design decision if the camera was aimed for snapshooters and toy camera users. In my experience, it is very rare to shoot landscape without stopping down to f/8 or f/11. Therefore, the lens should be focused at the hyperfocal distance of f/8 or even f/11 to extend the close shooting capability of the camera. It is very distracting and even unpleasant to see blurry subjects and sharp background. I would rather see crisp foreground and slightly blurry background. All these are better for snapshooters and does not interfere landscape photography at all. Therefore, I strongly hope that Zenit makes next generation panoramic camera with a 28mm lens focused at 3m or 3.5m. (Better yet is to make a zone focus camera, but it may make the rotating platform overly complicated.)
For now, I have worked out a quick hack to change the focusing distance of Horizon Perfekt from its default value to about 3 to 3.5 meters. This mod requires a piece of duct tape and a sharp pair of scissors, and it will be described in a later section.
Limited shutter speeds
This camera has two swing speeds and 3-4 shutter speeds for each swing speed by varying the shutter slit width. While the 1/500 sec end of the shutter speed is very adequate, the 1/2 second end is inadequate. Since I shoot a lot of nightscape photo, I frequently expose for 10 to 600 seconds. Realistically, 4 seconds would be much better than 1/2 sec and 10 seconds would be highly useful. I understand that this may be too much to pack in a single camera, so I hope Zenit makes Horizon Night model in near future. I will buy a second Perfekt if this happens. Presumably this only requires minor modifications on the existing clockwork mechanism.
Shutter Slits
The lens is capable of very high contrast image, as you can see in example pictures above. However, there is annoying tails on strong light sources (such as street lights) that extends quite far from the light source. This is because the edges of the slits (on the rear side of the lens, inside the film chamber) are reflective, although they are black. The inner plastic slits that changes its opening width with the shutter speed dial are the most reflective. These edges must be made flat (matte) black to minimize reflection. If Zenit makes this improvements, the image quality will be instantly improved. See Reducing Internal Reflection section below for details.
Viewfinder
Although I don't expect Cosina quality viewfinder on a camera like this, the viewfinder of this camera is pretty cheaply made, and it is impossible to make precise framing. You can try to look in from different eye posision and you'll know what I mean.
The viewable area of the viewfinder is smaller than that of the taking lens. What it means is that the picture on the film may register that ugly person standing just outside the area you see in the viewfinder. Or it may be your dirty finger, luckily out of focus this time.
To avoid this problem, the viewfinder should be made larger for easy viewing, and increase the viewable angle to a few degrees larger than the taking area. Then the approximate taking area should be indicated by a line box. This may require significant change in the viewfinder optics from the current design, but I would pay extra for this feature.
Back Cover
The film chamber and film guide rails are made from a metal, and this part is very rugged. However, the film back pressure is given by a flimsy plastic part formed on the plastic back door. This area is mechanically not very rugged and it also appears to be susceptible to wearing. I hope Zenit improves this part in the next model.
Shutter release button
The shutter release button is pretty heavy. It is just as heavy as most cameras with lock-needle exposure automation. It's so heavy that the camera cannot be triggered by an air shutter release cable. Therefore, I can't think of an easy way to take self portraits with this camera, perhaps except for a screw-on self timer unit.
I also think that for this camera, bottom plate may be a better place to put a shutter button. It's easier to push in a heavy shutter button with a thumb, especially if the camera is held in the "proper" way for this camera to avoid fingers getting into the picture.
Tripod screw
Tripod screw is held in place by its retaining ring around it. This frequently becomes loose during use. Users should make sure the retainer is tight at the end of each shooting session (if you use a tripod or monopod, the screw usually becomes loose soon after shooting). I secured my tripod screw and retainer by Loctite medium strength (242) or product number LOC-24221 or LOC-24231.
Film rewinding crank
This camera requires a bit more force to rewind film compared to most other cameras, due to long and complicated film path. Film rewinding crank is difficult to operate, even compared to some Japanese compact cameras from 1970s, before motorized cameras became popular. Even slight redesigning of the shapes and dimensions of the crank may improve the handling greatly. I personally do not mind if the rewinding crank was built on the bottom plate of the camera.
Spirit Level
This camera's spirit level is very useful, but not as responsive as one would hope. The response is sluggish. Also, the spirit level is very hard to visualize in dim light, both from the viewfinder or from the above. It would be helpful if they could incorporate an LED backlight for this purpose. (Note: this author shoots nightscape with this camera.)
Lack of Cold Shoe
Swing panoramic camera cannot be used with an electronic flash. However, a cold shoe would be useful as a platform to attach a light meter, such as Sekonic L-208.
Filter set
The camera has proprietary filter attachment, but it comes with a UV filter, a ND filter (2x) and a yellow-green filter. I don't know of any other filter that fits this camera. I personally don't see much use for the UV filter, since most films made by top tier manufacturers incorporate UV-blocking layers. I also find very limited use for the 2x neutral density filter. I hope it was 4x or even 8x to expand the exposure option when the camera is loaded with fast films.
Also, I'd like to have an orange (4x) filter and an infrared filter. I think it would be fantnastic to have an IR filter for this camera. Panoramic infrared images taken with Kodak HIE or vintage stock Konica IR 750 would be a very interesting project, although it may be very difficult to master.
Using Horizon Perfekt
Light meter
There are a lot of photographs taken with this camera on the web. Many poor quality pictures are apparently taken with inaccurate exposures. Even a simple, el-cheapo meter like Sekonic L-208 is useful and adequate for this camera. I use L-408 (spot and incident) when size is not an issue, but L-208 is also very useful.
Monopod
The camera comes with a grip bar to hold the camera, but I find it useless. The camera is much better used on a monopod, which not only provides comfortable grip but also provides stable camera support for 1/8 and 1/4 second exposure. While 1/2 sec is possible, it is probably best used with a tripod.
Fast film
Since the camera features a fixed focus lens (no focusing mechanism), it is important to stop down the lens whenever possible, for sharp image. Although a tripod can provide sturdy camera support for long exposures, the reality is that the exposure is limited by the 1/2 sec shutter speed limit of the camera. All these come to is that you're better off using film that's a stop or two faster than you would with a 35mm SLR for the same lighting condition. I like Kodak T-MAX P3200 b&w film (used at EI 1600) and Fujifilm Pro 800Z color negative film.
Film filing pages
Many 35mm users prefer to cut films to 6 strips of 6 frames. However, negative strips made by Horizon panoramic cameras won't fit very well in file pages (Negative Sleeves) of this type. Strips of 4 frames are too long, but there will be 7 strips of 3 frames. Also, the pockets for 6-frame strips are too long to handle 3-panoramic frame strips. Therefore, it is useful to use negative pages for 7 strips of 5 frames for negatives made with this camera.
Modifying the focusing distance
As mentioned above, the camera is focused at about 10 meter distance. This is very inconvenient for snapshots and indoor photography. I have worked out a quick hack to change the focusing distance to 3 to 3.5 meters.
Material: The modification requires duct tape, a sharp pair of scissors, and tweezers. The hack is reversible. In the example below, I used 3M Scotch Transparent Duct Tape from an office supply store. The thickness is about 0.18mm.
Theory: In order to change the focusing distance, the lens-to-film distance must be extended by about 0.15 to 0.19mm. These numbers are simply derived from the thin lens formula: 1/p + 1/q = 1/f where p is the subject-to-lens distance, q the lens-to-film distance and f is the focal length of the lens. First placing p = 9.9 and f=0.028, q is found to be about 0.0281 meters. Using this number and desired value for p (3 or 3.5 meters) the increase in q must be about 0.15 to 0.19 millimeters. Luckily, the thickness of our favorite duct tape falls in this range!
The modification is to cut two narrow strips of duct tape and firmly affix them on the film rails, with ample coverage on both ends of the rail (tape must be longer than the film rail), while making sure that the tape does not interfere the film path or the image area.
If done properly, the modification is durable for at least several rolls of films. But the tape may wear out, especially during rewinding process. With the modified camera, be gentle with the film advance lever and also rewinding crank. The key to minimize the wearing of the tape is to make the strip as long as possible, to cover the both ends of each film rail with good margin. Securely placing tape ends may be difficult. I find it easy to cut a business card to about 2cm width and push in the tape with it. The tape should end distal to the point where the film touches; otherwise, the tape end gets lifted by the film perforation and gets messy after rewinding each roll of film (i.e., avoid that).
When possible, choose tape that is made from hard plastic and is smooth on the surface to minimize the friction. Tapes with stronger adhesives, hard and smooth surface and lower friction may withstand many rolls of films without replacement. Examples of things that might work better are aluminium tape, copper tape and thick hard plastic tape. Before trying in the camera, measure the thickness. Please experiment with various tapes, and please let me know when you find tapes that work very well.
Here's the relation of thickness to focusing distance.
Horizon Perfekt focus modification
| Focusing distance | Tape thickness |
| 2.0 m | 0.32 mm |
| 3.0 m | 0.19 mm |
| 3.5 m | 0.15 mm |
| 4.0 m | 0.12 mm |
| 5.0 m | 0.08 mm |
| 9.9 m | 0.00 mm (camera default) |
Depth of field for Horizon Perfekt
Circle of Confusion: 0.028mm. Distance in meters.
| Distance | f/2.8 | f/4 | f/5.6 | f/8 | f/11 | f/16 | |
| 3.0 m | near | 2.31 | 2.11 | 1.87 | 1.62 | 1.36 | 1.11 |
| (modified) | far | 4.29 | 5.21 | 7.51 | 19.9 | ∞ | ∞ |
| 3.5 m | near | 2.59 | 2.34 | 2.06 | 1.76 | 1.46 | 1.17 |
| (modified) | far | 5.39 | 6.94 | 11.7 | ∞ | ∞ | ∞ |
| 10 m | near | 4.98 | 4.12 | 3.32 | 2.60 | 1.99 | 1.49 |
| (default) | far | ∞ | ∞ | ∞ | ∞ | ∞ | ∞ |
| hyperfocal | distance | 9.90 | 7.00 | 4.95 | 3.50 | 2.47 | 1.75 |
In my photographs, the point of sharpest focus (assessed visually on high resolution scans) is about 2 to 6 meters away, and distant objects are slightly blurry when shot with f/4 or f/5.6. This confirms that my hack is very effective to meet the goal.
Circle of confusion
When discussing depth of field, one must assume acceptable degree of blur. This is circle of confusion. It should be determined by the maximum print size, print sharpness requirement, the the resolution of the film and the camera optics, and other factors. 0.028 mm is commonly used for 35mm format from pre-digital era. This is equivalent to 1 pixel blur for 900 dpi scan, or about 4.4 pixel blur on 4000 dpi scan. That is, if you shoot an object at the edge of DoF (see table at the end of this article), you get this degree of small blur. The resolution of pictorial films is no higher than 200 line pairs per millimeter even in an ideal high contrast condition. That is, the 0.028mm circle of confusion is at least 2.2x smaller than the blur you get from the limited film resolution. The overall limiting factor of the image sharpness is the resolution of the film. This is not necessarily bad, especially if you scan the film and print digitally; Photoshop's smart sharpen function is so good and flexible. If you use just right amount of smart sharpening function to alleviate the blue from film resolution, you are also expanding the overall effective DoF from the table above, by sharpening out the additional small blur from the circle of confusion.
Reducing Internal Reflection (work in progress)
The Arsat 28 mm f/2.8 lens equipped in this camera is capable of very high contrast image, as you can see in example pictures above. However, there is annoying tails on strong light sources (such as street lights) that extends quite far from the light source. This is because the blunt edges of the shutter slits are reflective. This camera has two layers of slits in the film chamber, but the larger offender is the inner slits made from black plastic. Zenit should have made these slit edges beveled and textured, so that the reflection would go away from the film surface.
One quick hack that can be made in the hands of end users is to coat the slit edges with a non-reflective paint. Most black paints are just as reflective (shiney) and ineffective for this purpose. It has been suggested by Richard Knoppow that Krylon Ultra-Flat Black paint (comes in 12 fl. oz. spray size) is the least reflective and most light-absorbing paint that is readily available in almost any hardware store. This paint can be sprayed in a used film canister and then applied to the shutter slits by using the tip of a toothpick.
The efficacy of this modification is currently being tested. This section will be updated soon.
