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My limited research has identified lenses at 30mm, 45m, 50mm, available in the Pentacon six mount, but no wider thus far. Clearly using a 30mm MF fisheye as an APS-C shift lens would give wierd results- perspective correction with a distorting lens!
Strangely (as an architecture student), its actually the potential for creative focus with a tilt lens, which appeals far more than perspective control shifting.
__________________ Pentax K100D Super + 18-55 lens |Sigma 24/2.8 |Vivitar MC 28/2.8 |Pentax M 50/1.7 |Meritar 50/2.9 |Industar 50-2 50/3.5 |Vivitar Series 1 70-210/3.5
Hi Richard,
Much of my interest is in the control of perspective with the tilt function. I am planning on making a homemade shift lens. I will fabicate the tracks to allow the shift. A lens with an interchangeable mount will be needed to provide sufficent room for the tracks, while maintaining infinity focus. A small or recessed rear lens element is also needed to allow the lens to move an effective distance, off center.
The ASP-C sensor will actually allow a FF 35mm lens to cover the image circle necessary for coverage while the lens is offset. Some hackers have used medium format lenses to gain these requirements, but this results in a heavier setup. The lenses can also be quite expensive.
Dave
Originally Posted by Confused
Hi Dave
Just don't forget to remember that due to the unavoidable focal length crop factor (x 1.5) involved when attaching a conventional perspective-correction or shift-lens to a DSLR equipped with an APS-C sensor (such as the one inside the Pentax K10/20D/100DS), a normal 28mm lens regrettably converts into 42mm (28 x 1.5) and a 35mm lens becomes 52.5mm (35 x 1.5)
(in relative 35mm film terms). This pretty-much defeats the original purpose of perspective correction lenses when photographing tall buildings etc, especially when used in conjunction with an APS-C DSLR. Unfortunately the least expensive digital equivalent to the above-mentioned scenario involves shelling out for a full-frame DSLR body (No focal length crop factor to worry about !!) such as a C***n 5D fitted with one of their 24mm TSE lenses. However, you'll need pretty deep pockets (approx £2,500.00 or $5,000.00 !) if you intend following this route ! Even then, it's not all plain sailing, because you may encounter noticeable misaligned colour-shift in the resulting digital images taken with the aforementioned combination at the extremes of the lens's shift mechanism. This anomaly is primarily due to the different manner in which light strikes a 'flat' film emulsion than it does when it arrives indirectly at the light-wells on the underside of the surface of a CCD sensor, but that's another 'can-of-worms' entirely !
Alternatively, if you can leave sufficient space around the object you are photographing when using a normal APS-C wide-angle lens, you will discover that optical distortion such as 'converging verticals' can easily be corrected using inexpensive digital editing software like PSPro or Photoshop Elements 6. Hope this info helps somewhat.....
barondla,
The Pentax 6x7 registration distance is 84.95mm. You would have to adjust it with shims if needed. This would only work if the mount was thinner then 84.95mm. I read the write and it said the the lenses have non-interchangle mounts.
If I bought the Arax adapter wonder how difficult it would be to convert MF lens mount to Pentax 6X7? May not be correct distance from sensor.
thanks
barondla
Enter the POINT & SHOOT CONTEST #7 in the P&S forum. Any camera except slr. Any brand. Any subject.
Much of my interest is in the control of perspective with the tilt function.
I'm almost probably talking through my backside as usual, for reasons which will become blindingly obvious in due course ! Therefore please forgive me for temporarily side-stepping the technical complexities/difficulties involved. Nevertheless, the thought occurred to me that you might just possibly achieve a 'tilting' facility using something along the lines of a 35mm
'macro track-bellows' (cheapish secondhand), equipped with a rising-front mechanism of some description ? I don't know if such a commercially available product already exists for Pentax cameras and you'd probably lose all form of automatic metering etc. The nearest thing I can find at short notice is illustrated in the link below for N***n SLR's.......just scroll down this page and you'll see the type of contraption (PB-5 Bellows) I'm on about, although it might have to be 'slightly' modified to achieve the tilting action !
__________________ K10D x 2 & D BG-2 Grip, Tamron AF 18-250mm f/3.5-6.3 XR Di II LD IF Macro W/A Zoom Lens, Sigma 10-20mm F4-5.6 EX DC HSM Lens, Giottos MTL9351B Tripod, Metz 48 AF-1 Flashgun, Lowepro Nova 3 AW Bag
Hi Richard,
I have seen bellows units with a front lens mount that would tilt. This would be great for some macro use situations, but it won't get infinity for buildings and such. I might add a horizontal tilt to the rear mount of one of my bellows units. Adding it to the front would be to difficult and may not work as well. I seen an adapter which allows a medium format lens to be mounted on a 35mm for around $600 without the lens. It just might be a fun project to use a full frame 35mm lens on a digital. I have two Soligor 35mm T4 lenses for this effort. I might make one a tilt and the other a shift lens. I got them off ebay and have a total of $12 invested in them both. I think that I will have to make the rails, since I have not found anything that could be adapted for the job. I'm just having fun in my old age.
Dave
Originally Posted by Confused
Hi again Dave
Re your statement:
I'm almost probably talking through my backside as usual, for reasons which will become blindingly obvious in due course ! Therefore please forgive me for temporarily side-stepping the technical complexities/difficulties involved. Nevertheless, the thought occurred to me that you might just possibly achieve a 'tilting' facility using something along the lines of a 35mm
'macro track-bellows' (cheapish secondhand), equipped with a rising-front mechanism of some description ? I don't know if such a commercially available product already exists for Pentax cameras and you'd probably lose all form of automatic metering etc. The nearest thing I can find at short notice is illustrated in the link below for N***n SLR's.......just scroll down this page and you'll see the type of contraption (PB-5 Bellows) I'm on about, although it might have to be 'slightly' modified to achieve the tilting action !
I actually ordered the Arsat 35 mm tilt/shift lens for my k10d three weeks ago . I knew about the lens lenght issue but I bought it mostly for the tilt mechanism. I haven´t recieved it yet so I have no samples to show you
If I have this right, the 'shift' bit of 'tilt-shift' only means that the whole lens can move laterally relative to the camera body?
So correct me if I'm wrong, but it should be a fairly simple attachment to create, with the only really problematic part being light leakage into the gap between the body and lens mount?
Edit: Given engineering knowledge, of course! I have none, sadly.
__________________ Body: K10D
Lenses: DA 18-55 f/3.5-5.6 :: A 70-210 f/4 (For Sale) :: M 50 f/1.7 (For Sale) :: SMC Takumar 50 f/1.4 :: Tamron SP 90mm f/2.8 :: Sigma 10-20mm f/4-5.6 EX DC
Accessories: AF-540FGZ :: Sto-Fen Omni-Bounce :: Slik Sprint Pro :: Giottos MH-1001 :: LowePro Topload Zoom AW
If I have this right, the 'shift' bit of 'tilt-shift' only means that the whole lens can move laterally relative to the camera body?
So correct me if I'm wrong, but it should be a fairly simple attachment to create, with the only really problematic part being light leakage into the gap between the body and lens mount?
Edit: Given engineering knowledge, of course! I have none, sadly.
Add a 360 degree rotation capability so you can shift in every angle. I think that it is not a problem of being easy to do, is more a problem of doing it in a way that can be used for a long time without breaking-throwing debris to the sensor.
__________________
"Work wears us out. That proves that we were not made to work..." Raymond Ruyer
It should be a fairly simple attachment to create, with the only really problematic part being light leakage into the gap between the body and lens mount ?
Perhaps not necessarily as 'simple' as it might first seem ! Effectively there are a number of means to accomplish this task, such as the manufacturing method adopted by Canon in their TSE range of lenses, illustrated in the link below:
However, demand for such lenses remains relatively minuscule nowadays and as a result, their cost is usually prohibitive.
Failing that, the conventional route tends to follow the plate camera/technical design in varying film dimensions
(typically 5" x 4" or 10" x 8" sheet film emulsion), involving bellows & rising front/tilting rear mechanisms, as shown in the link below:
__________________ K10D x 2 & D BG-2 Grip, Tamron AF 18-250mm f/3.5-6.3 XR Di II LD IF Macro W/A Zoom Lens, Sigma 10-20mm F4-5.6 EX DC HSM Lens, Giottos MTL9351B Tripod, Metz 48 AF-1 Flashgun, Lowepro Nova 3 AW Bag
I understand that to do it "right" takes quite a lot of precision engineering, especially if it's going to be up to spec for Pentax/Canon/etc. engineers.
I was just thinking if you set aside the "tilt" aspect for the time being, it could be a cool little DIY project. I saw a few tutorials on how to do it with a body mount cap, 'bellows' type toilet plunger, construction paper, and some tape, I was just trying to imagine a way to make one on rails to have a more precise 'shift' lens... no tilt.
__________________ Body: K10D
Lenses: DA 18-55 f/3.5-5.6 :: A 70-210 f/4 (For Sale) :: M 50 f/1.7 (For Sale) :: SMC Takumar 50 f/1.4 :: Tamron SP 90mm f/2.8 :: Sigma 10-20mm f/4-5.6 EX DC
Accessories: AF-540FGZ :: Sto-Fen Omni-Bounce :: Slik Sprint Pro :: Giottos MH-1001 :: LowePro Topload Zoom AW
yenemy,
Most of these lenses are extreme retrofocus with a much recessed rear element. The hard part is getting a lens with space for the rails between the lens and camera, while focused at infinity. It also has to have a very large image circle to cover the frame while off center. I have a 35mm Soligor full frame lens which should work. The rear element sticks through the bayonet, but still allows 10mm of shift off center. This is because of a small diameter rear element. The FF image circle should cover the ASP-C sensor when shifted. We will see. Some shift lenses use dual rails set at 90 degrees to get both axis.
Dave
[quote=yenemy;I was just thinking if you set aside the "tilt" aspect for the time being, it could be a cool little DIY project. I saw a few tutorials on how to do it with a body mount cap, 'bellows' type toilet plunger, construction paper, and some tape, I was just trying to imagine a way to make one on rails to have a more precise 'shift' lens... no tilt.[/QUOTE]
Hm hm, interesting. Thanks for the info, Dave. I read in one of those tutorials that all the people who tried it with a plain 35mm lens ended up with a tilting-plunger-bellows-macro lens instead of a tilt-shift, and I guess that's why
I've seen some eye-opening wide-angle shift lens applications in real-estate photography, and I was considering doing some experimenting, basically to see if I could get decent results without forking over an unholy amount of money for a tilt-shift wide angle lens. I guess until I win the lottery, I'll be stuck with my LBA for the Sigma 10-20, and a possible Lensbaby waaay down the road.
... or I could actually use the lenses I have!
__________________ Body: K10D
Lenses: DA 18-55 f/3.5-5.6 :: A 70-210 f/4 (For Sale) :: M 50 f/1.7 (For Sale) :: SMC Takumar 50 f/1.4 :: Tamron SP 90mm f/2.8 :: Sigma 10-20mm f/4-5.6 EX DC
Accessories: AF-540FGZ :: Sto-Fen Omni-Bounce :: Slik Sprint Pro :: Giottos MH-1001 :: LowePro Topload Zoom AW