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Tech Cams: Why I like tilt

Jack

Sr. Administrator
Staff member
One degree of tilt...

Here is an exemplar image showing what tilt can do. First off, the light was changing fast and so I had to move very quickly to get this before the rainbow disappeared -- so it is not framed ideally, and in fact this a crop from the full IQ180 frame to get the old ruin and the bow out of the dead center. Anyway, the crops are still full size and work for the purposes of this example.

First, the cropped full frame image -- about 20MP taken off the top and LH edge of frame:



Specs for the shot were early AM light and rain, 40HR-W at f8, 1/30th at ISO 35, 10mm RISE and 1 degree forward tilt to hold foreground through infinity sharpness at f8. LCC was taken and image was processed in C1, then adjusted slightly for contrast in PS before creating the web crops and jpeg.

Here is the crop from about two feet in front of my right tripod leg:



Here is a crop showing ground level at mid frame distance , as well as the structures there, as well as the far mountain in decent light (and no rain) at infinity:



Note: There is a slight "hot spot" mid frame near the base of the rainbow. At first I thought this was due to the rain right there -- and it could be -- but I also had similar spots on higher contrast images taken the day before and day after this one. So right now, I am puzzled. I originally tested the lens in high-contrast light and did not get any hot-spotting, but now I do. Just realized it was raining most of the time, so perhaps I got some moisture in the internal surfaces of the lens, need to check that out ASAP...
 

Guy Mancuso

Administrator, Instructor
Looks like moisture on the inside of the lens from humidity. Had this happen a lot when i was in Brazil
 

Jack

Sr. Administrator
Staff member
Actually, after thinking that, I ran home at lunch to dry it out. It turns out it is from the lens caps you and I use -- there is a little sticker inside center, and it when in the bag, it compressed just enough to rub a wee bit of goo on the direct center of the front element -- only about 2mm in diameter, and why I never noticed it. Feeling very, very stupid :shocked:
 

darr

Well-known member
Wonderful shot Jack, even with the lens cap problem--always learning new stuff us photogs!

Darr
 

Jack

Sr. Administrator
Staff member
Damn that was silly of them to put in there to start with.
Actually, I think it's there on purpose to prevent the hard plastic of the cap from scratching the lens. The irony is I used these because the factory slip on Tech lens caps are so flimsy they can easily compress to the rub the front element if you're not careful -- I learned this in my LF days as LF lenses use the same press on caps. The hard style we use for our regular lenses are a flat designed cap, and I suspect that sticker is there as a protective pad. I've already moved to domed hard caps, left over form various Mamiya lenses, and they appear to be perfect candidates for tech lenses with shallow recess front elements :thumbup:
 

Jack

Sr. Administrator
Staff member
Wonderful shot Jack, even with the lens cap problem--always learning new stuff us photogs!

Darr
Thank you Darr! It was one of those "wish I had 5 more minutes to grab it properly" shots ;)
 

gazwas

Active member
Note: There is a slight "hot spot" mid frame near the base of the rainbow. At first I thought this was due to the rain right there -- and it could be -- but I also had similar spots on higher contrast images taken the day before and day after this one. So right now, I am puzzled. I originally tested the lens in high-contrast light and did not get any hot-spotting, but now I do. Just realized it was raining most of the time, so perhaps I got some moisture in the internal surfaces of the lens, need to check that out ASAP...
Jack, this is so weird you posting about the same problem I had with a 40HR-W I purchased to possibly replace my 43XL. I assumed as the 40HR-W was such a widely used lens and this issue had never been reported before I had purchased a dud copy of the lens and didn't bother mentioning it on here.

A quick example of the flare spot on my 40HR-W can be seen below. It was always in the centre of the lens in contrasty lighting and was plain as day when the spot was over dark foliage. Interior shots with soft lighting I could not detect the spot, but this was not to say it wasn't there. I say this because I use an Arca ML2 and focus on the ground glass with a loupe and for the life of me I couldn't get a good focus by eye with this lens. My interest in the 40HR was the f4 aperture for brighter focusing on the GG but what looked ok on the GG in the centre was quite a margin out when viewed on the laptop, surprisingly the f5.6 43XL was always there or very nearly. It was as if there was no contrast to focus the lens properly.

I could shoot in the same lighting conditions (white sky's, dark foreground) and replicate this issue every single time over a period of 4 days testing. Move my P65+ around the image circle and the spot would stay on the same tree in the centre of the lens but shifted up, down, left, right etc around the frame. It wasn't a camera problem as I did the same shots on the 43XL after each other and they did not display any of the same problems.

I ended up getting a refund on the lens because of this problem and stuck with the very excellent and predictable 43XL. I've considered testing the lens again to see if the problems are on a different manufacturing batch but there was so little difference between the two for light fall off and sharpness I think the 43XL is the better choice for me.

I would seriously consider thoroughly testing your lens again as it might be something more than dirt. My copy was brand new out of the box and the first capture I noticed it and no amount of cleaning and blowing changed anything.
 
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vjbelle

Well-known member
Jack,

This is one of the big advantages of the Arca and Cambo systems over the Alpa..... Tilt on the Alpa is limited to 80mm. But..... I own lots of Alpa stuff so I'm kinda married to it. Could you maybe comment as to why Alpa would offer two different tilt adaptors? I can't imagine why anyone would require a tilt of over 6 degrees. It would be beneficial if there was a series on tilt showing various lenses, short and long, with different tilts....... lots of folks could lean.

Victor
 
Victor, for macro and in some cases external architecture there are times when you want more. Also you can put it on the back of the camera and use it to swing the back instead for perspective correction. There are some nice creative effects, especially in portraiture that also use more aggressive tilt. Lots of things in fact!

I would also point out the Arca can tilt a short lens, but on a long lens will move the front element quite a distance as it's swinging around way out there. You'll probably get some clipping of the image. The Alpa can put the tilt on the front or back, but shortest is 80mm as pointed out. Horses for courses. The Linhof techno is a good choice.

Paul
 

Jack

Sr. Administrator
Staff member
I would seriously consider thoroughly testing your lens again as it might be something more than dirt. My copy was brand new out of the box and the first capture I noticed it and no amount of cleaning and blowing changed anything.
I tested mine thoroughly the day I got it, including harsh into bright sky shots, and had ZERO hotspotting. I even went back to confirm those. This spot was clearly from a 2-3mm circle of goo on the dead center of the front element. It looked like and of course affected the image just like a spot of vaseline smeared on the front element :rolleyes:
 

Jack

Sr. Administrator
Staff member
Jack,

This is one of the big advantages of the Arca and Cambo systems over the Alpa..... Tilt on the Alpa is limited to 80mm. But..... I own lots of Alpa stuff so I'm kinda married to it. Could you maybe comment as to why Alpa would offer two different tilt adaptors? I can't imagine why anyone would require a tilt of over 6 degrees. It would be beneficial if there was a series on tilt showing various lenses, short and long, with different tilts....... lots of folks could lean.

Victor
I shoot an *Arca RM3Di* not an Alpa, just for clarification. I have no idea why Alpa would offer two distinct tilt assemblies. I am sure Thierry can get us the correct answer, but if it can be mounted on the back as well, that could explain it. Back tilts (most often are swings for architecture) are often used to "square up" offset geometries, and this typically requires more movement than for PoF (Plane of Focus) changes. Additionally, rear swing for geometry correction usually needs the lens tilted (or swung) opposite to counter the focus changes from swinging the back. This (and perspective-correct product photography) is probably the main area where a full-movement view cameras really earn their keep...

Re PoF changes. The total amount of tilt required to affect the PoF is dependent on the focal length and the subject distance; longer focal lengths require more tilt, and closer subject distances require more tilt. For tech use, I would think 5 or 6 degrees is more than adequate for up to 150mm lenses and relatively closer subjects. In most cases, a 35-50 lens at infinity will only need 1 degree, and a 70-90 at infinity maybe 1.5-2 degrees...
 

Jack

Sr. Administrator
Staff member
Good work, Jack! You've convinced me that an Alpa T/S adapter is an absolute necessity :):)
Cool David! Just be aware that I believe the Alpa TS adapter is only usable on 80mm and longer lenses, so it won't help with PoF changes for shorter lenses.
 

GrahamWelland

Subscriber & Workshop Member
When I asked about the Alpa 6 vs 12 degree adapters I was told that the 12 degree version was simply a newer design (re-design). There's a slight difference in price but thats all. Btw, you can almost buy an Arca body for the price of the adapter thanks to the strength of the Swiss Franc :(

The tilt/swing on wides is definitely a nice feature that Alpas lack. Focus stacking becomes a way of life unfortunately amongst the "tilt challenged".
 

gazwas

Active member
I tested mine thoroughly the day I got it, including harsh into bright sky shots, and had ZERO hotspotting. I even went back to confirm those. This spot was clearly from a 2-3mm circle of goo on the dead center of the front element. It looked like and of course affected the image just like a spot of vaseline smeared on the front element :rolleyes:
OK Jack. It does sound like it was the goo on the front element but I'm just making you aware that in my experience it only showed under certain conditions with the lens I had. Bright sunny days with blue skys or softly illuminated interiors there was zero spotting but shoot a green field/garden on an overcast whited out sky day and hey presto Mr Spot appeared on every shot....... Lens looked perfectly clean.

It's worth another test under these conditions IMO and ideally the same location as your above posted image.
 

Christopher

Active member
I have Seen these spots before, from my experience they come from faulty shading. I could easily remove them by adjusting the lens hood. However, I have seen this effect strongest on the 150mm Schneider.
 

Thierry

New member
Yes, that's it basically, concerning tilts (or swings). Remember that it all works according to the Scheimpflug rule: the 3 planes (subject, lens and image planes) have to meet into a common line, if one wants to have the sharpness plane. Therefore, it needs a bigger tilt-angle (swing) when the distance is longer between lens and image plane to have these 2 planes to meet. This means in practice that since a longer focal length requires a longer distance from lens to image plane to be sharp (infinity being the smallest possible distance = focal length) as a shorter focal length, such long lenses also require a bigger tilt (swing) angle.

Also, since in studio one is closer to the subject, it needs also a longer lens to image plane distance as when focused on infinity (and basically one uses longer lenses for stills and macro), thus a bigger tilt (swing) angle is needed, as compared to shots at infinity.

Thierry

Re PoF changes. The total amount of tilt required to affect the PoF is dependent on the focal length and the subject distance; longer focal lengths require more tilt, and closer subject distances require more tilt. For tech use, I would think 5 or 6 degrees is more than adequate for up to 150mm lenses and relatively closer subjects. In most cases, a 35-50 lens at infinity will only need 1 degree, and a 70-90 at infinity maybe 1.5-2 degrees...
 

Thierry

New member
As mentioned by Jack and in my previous post, it usually needs a very few degrees of tilt (swing) to get things sharp with short focal length lenses and with long shooting distances.

The Alpa Tilt/Swing +/- 0-6 Degrees Adapter is usually more than enough for most of the situations.

However, some photographers have asked us to build an TS adapter with +/- 12 Degrees, for setups in studio in Macro situations, for extreme perspective corrections, etc .... That's the reason why Alpa has 2 different adapters.

ALPA 0-12° (24°) tilt/swing adapter, multi-use

Thierry

I have no idea why Alpa would offer two distinct tilt assemblies. I am sure Thierry can get us the correct answer, but if it can be mounted on the back as well, that could explain it. Back tilts (most often are swings for architecture) are often used to "square up" offset geometries, and this typically requires more movement than for PoF (Plane of Focus) changes. Additionally, rear swing for geometry correction usually needs the lens tilted (or swung) opposite to counter the focus changes from swinging the back. This (and perspective-correct product photography) is probably the main area where a full-movement view cameras really earn their keep...
 
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