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Talking Technical on Tech Cameras

Jae_Moon

Member
The current Tech Camera users and 'soon to be' need many more detailed technical discussion concerning the use of camera, away from 'brand' based discussion. Focusing is a Tech Camera issue not ALPA's or Linhof's, Tilting properly is a Tech Camera's challenge not A-S's or Cambo's.

So, I am starting a new thread to talk about many technical issues we are facing with Tech Camera. I will start with my experiences of challenges that I faced and the solutions that I came up for my Tech Camera.

I hope you don't mind if I am reposting two previous posts from "Arca Rm3di" to start my story.

Jae M
 

Jae_Moon

Member
I've had my Rm3di for as long as Jack has, since August of 2011. I had F-Metric Compact 6x9 before that and used both camera with P45 DB.

The focusing is the main challenge with both View and Technical camera whether one is using Tilt or Swing or not. Tilt and/or Swing just makes the challenge bigger, at least by a magnitude of 10. None of currently available methods of focusing; GG, LV, tethered shoot and using a laser range finder, are a perfect solution.

I am only going to talk about 'focusing' here, not 'composing' or 'Tilt.'

For me at least, GG is not an option. I tried too many different types of GG and loupes with my F-Metric and gave up on the idea of using GG with MFDB. Personally, I only have a limited experiences with the LV with MFDB, and I hope that we may have the 'perfect' solution soon. A tethered shoot provides the best possible focus but by means of trials and errors.

The reason why I picked Rm3di is based on the possibility of achieving the perfect focus every time utilizing its very precise 'helical' focus ring and precise measurement of object distances. It is my assumption that Arca-Swiss originally designed its Rm3di with the same design criteria. Arca-Swiss is finally making available 'E-module', which I am only familiar with by reading about it, to measure 'precise' distance.

Both ALPA and Arca-Swiss are providing means of 'precise' focus; HPF rings from ALPA and a built-in Helical focus from Arca-Swiss, with different twists. There are two significant differences between two methods; rotational pitch and indexing method. Many are focusing on either advantage or dis-advantage of the larger rotational pitch of helical focus ring of Arca-Swiss over the HPF ring of ALPA.

I will use the example of using SK35XL on both mounting methods.



As can be seen, Arca-Swiss helical ring needs to rotate approximately 4 times as much as HPF ring. You make your own conclusion if it is good for your workflow or not.

Another difference is the method of marking distance scale. HPF ring is marked with the actual object distance for a particular lens while A-S Helical ring is just simple index (0 to 34.4 for each revolution, up to 5 revolutions if necessary).

Each has both pros and cons; HPF ring eliminate one step of 'look up table' that A-S uses; measure the distance with a laser range finder then dial in the distance while you have to look up a table which converts the measured distance to a focus setting for Arca-Swiss. On the other hand, HPF ring only shows 9 discrete distance marking between 2.5 m and infinity while the look up table from Arca-Swiss shows 34 discrete focus settings for the same distance range. HPF ring has tick mark for each angular degree but has the actual distance marking at every 5 degrees (except first 5 degrees from infinity). For example, it show the distance setting of 9.64 m at 5 degree and 4.86 m setting at 10 degree, therefore, you have to make a quick interpolation if your distance measurement is 7.5 m to find the correct focus setting. Done? The answer is 6.5 degree. ALPA makes it available a print out of HPF ring setting for each degree in PDF format for each lens, and they are 7 pages per lens.

The real advantage of the simple indexing used by Arca-Swiss is when one takes advantage of an iPhone and some mathematic. It is possible to develop a 'lens equation' which converts the object distance into the required angular rotation for an individual lens, and run it on an iPhone. That's what I had in mind when I chose Rm3di and I've been using it from the beginning. Measure the distance with a laser finder, then tap in the number into an iPhone and it will show the exact focus setting; i.e., White 7.3

The development of 'lens equation' requires the combination of 'optical lens equation' and 'curve fitting' by numerical analysis. A simple 'optical lens equation' does not work in entire object distance range since the modern lenses for MF are very complex with multiple lens elements. It is necessary to measure the actual focus settings for different distances or just use the data provided by Arca-Swiss. I did my own measurement.

Can this method be used with HPF ring? It can be done if the distance markings are replaced with a simple angular degree indexing of 0 - 270, by pasting a simple adhesive tape over distance marking. It is not easy to find 37.5 degree from the scale marked with 9.64, 4.86,3.27, etc.

For me, Rm3di provides the best solution to make perfectly accurate focus under the presently available technologies; Leica Disto D5 and a home brewed program on an iPhone.

I will discuss the subject of Tilt or Swing on a separate post.


Jae M
 

Jae_Moon

Member
I discussed the challenge of making perfectly accurate focus using tech cameras with MFDB in previous post (#31).

A quick summary, at least in my case, the best possible method with the presently available technologies to achieve perfect focus is by using 'lens equation' with accurate object distance measurement and a precisely indexed focus ring. A lens equation, for a specific lens with a specific focusing system, can be developed mathematically. The 'lens equation' will provide the required angular rotation of a focus ring for a measured object distance.

First, I would like to 'rant' against all View Camera and Tech Camera manufacturers for their failure to promote (i.e. to educate their customers) properly how to use the features they are building into their camera. It is a shame that they let the customers to rely upon HF (hyper focal) or 'focus stacking' for proper focusing, or '35mm rule of thumb' for lens tilt calculation after spending a small fortune on equipment that boast 'multi mega pixels', '13 f-stop dynamic range' and 'lens with resolving power to see the sub atomic particles', etc. Why can they develop and provide more than a 'satisfactory' solutions to the challenges their customers face? Enough with ranting.

Let't talk about Tilt or Swing in Tech Camera application.



A simple geometric diagram for Tilt (both camera and lens) is shown above.

The Plane of Sharp Focus is defined by two points photographer select to be in 'sharp' focus, Near Subject (or Object) and Far Subject. Camera Height, Camera Tilt angle and a specific lens are also defined by photographer to compose the image properly. The lens Tilt Angle and the required Focus Distance are the results of these five input data (the location of Near and Far Subjects, Camera Height reference to the ground, a lens focal length and Camera Tilt Angle). In addition, Near and Far Wedges of Acceptable Sharpness (Angular DOF) are defined by a user selected CoC.

The real challenge of using Tilt or Swing with View Camera or Tech Camera is not finding a lens Tilt Angle but the required Focus Distance after a tilt is made. Harold Merklinger published two books (The Ins and OUTs of Focus, Focusing the View Camera) on the subject of Lens Tilt in details.

Once I was satisfied with the results of 'Lens Equation' in achieving a perfect focus with a measured Object Distance, I decided to tackle the challenge of Lens Tilt (or Swing). It is rather complex geometric calculations but doable using a spreadsheet, such as Excel or Numbers. It took me much longer than I expected (my mathematical brain atrophied significantly over last 40 years) but I completed the project and have been using since last Spring.


The picture above shows the setup I use for both leveled and lens tilted application. It maintains the exact geometric configuration between Rm3di and Disto 5 so I can always accurately measure the Object Distance or Near (Far) Object locations. Since all Disto measurement are offset from Lens Axis, Lens Nodal Point and DB sensor plane, proper corrections are made in the program.

Near (and Far) Object locations should be measured by their horizontal and vertical distance from the lens nodal point. Disto 5 has a function to measure them (Direct Horizontal Distance).

I made a quick shot this morning after reading "Torger's" comment. I used SK90, placed two $20 bills on the floor (1.96m and 3.22m away from the camera, and the nose of Andrew Jackson was the targets), camera was tilted 23.8 degree and the camera height was 0.96m. The required lens tilt was 4.82 degree and the calculated focal distance was 2.14m, therefore the index setting of Red 22.1.


Images are directly from C1 without any enhancement.

100% of Front US$20 bill.

100% of Back US$20 bill.

One additional picture I took while working on the program, Lens Swing. I superimposed 100% images of two blocks, front and back.



This is the one man's story to use a tech camera, Rm3di, for its full potential.

There are several mechanical designs of Rm3di which I wish they improve soon.

1. There are no indentations (mechanical click) for both vertical and horizontal shift center positions.
2. Thumb dial for Lens Tilt needs major improvement, for both accuracy of setting and ease of use.
3. Helical ring is too tight to rotate. I understand its need to stay at a set point but the friction could be much less.
4. Focus setting point should be a 'fine line' much closer to the index markers.

I will discuss my attempt of distributing the program commercially in next post.

Jae Moon
 

Jae_Moon

Member
I haven't quite got my head around Jae's math and how I would use the Disto 5 should I decide on purchasing one vs the E-Module though. I think further explanation for my aging grey matter is required (hint hint) :)!


In my two previous posts, I discussed methods I developed to maximize the usability of a Tech Camera, in my case Rm3di. It is very important to remember that I am talking about techniques of using a 'machine' accurately, not about creating artistic masterpieces. Some may argue that my methods of focusing is an overkill and there are ways to get 'good enough' instead of 'absolute.' Again, I am being a mechanic who 'fine tune' a Formula 1 car for a driver so he can take advantage of it and show its maximum performance on the track and may win the race (for me, as a driver, I am taking advantage of the camera to it's maximum potential but haven't won any race yet. But just puttering around with a finely tuned machine is lots of fun too).

The main attractions of a Tech (and View) Camera to a photographer are two folds (my personal opinion); first, the best possible optical lenses available; second, mechanical 'movements' - shift, tilt, swing and accurate focus ring. The main challenges of a Tech Camera to a photographer who purchased it is its difficulty to use, mainly how to focus accurately with or without Tilt/Swing.

CONTROL based on visual feedback is very powerful and useful. See how we steer cars, we don't measure the angle of turn we need to make before making a precise turn of steering wheel (in other hand, we usually end up in accidents if we try keep on driving with badly fogged up windshield), see how Apollo 13 crews steered the crippled module to a successful reentry based on visual feedback of seeing the earth through the module window (but they could do it only because they are NOT ordinary weekend Piper flyers).

A Tech Camera with MFDB lacks an 'Excellent' visual feedback to focus an 'Excellent' lens via an 'Excellent' camera movement. In control theory, the weakest link determines the final result. The combined accuracy of a Tech Camera is 60% if the accuracy of the visual feedback using a GG (or my dated P45 display) is 60% even with 100% accurate lens and camera movement. The same analogies apply to the Lens component of Tech Camera (reduced lens performance by stopping down the aperture) and Focusing component (i.e., relying on HFD or Infinity focus setting).

How do we measure distance (to focus accurately)?

- It is not likely a Tech Camera will have an Auto Focus such as Nikon and Canon.
- LiveView may solve the problem in 2-3 years (IQ4xx).
- A tethered shoot has its place.
- eModule from A-S? First of all, it is only for RM camera from A-S. I only know how it work and what it does based on what I have read from this Forum. My present impression is that it is an excellent concept but not-so excellent method of measuring distance. It measures (let me know if I am wrong) the distance the way we manually focus a SLR camera, rotate a focus ring until the image is sharp, then translate the angular rotation into focus distance. I don't know yet how many rotations it requires to focus from Infinity to let say 1 meter. With A-S Focus Ring, SK35 rotates slightly over 360 degree (1 rotation), SK47 rotates 720 degrees (2 rotations), and SK90 rotates 1,620 degrees (4.5 rotations) to focus from infinity to 1 meter. The same control theory applies here, the weakest link determines the final result. The number of rotation of eModule focus ring determines the effectiveness of Rm3di's helical focus ring. If the focus ring of eModule rotates 360 degree (Canon 5DII rotates approximately 90 degree), its accuracy with SK35 will not diminish, with SK47 it will diminish to 50%, and with SK 90 it will diminish to 25%. (I apologize in advance if eModule reads the distance by other means, not relying on the angular rotation of focus ring.)
- I gave up on GG for my own reason and do not have opinion on it anymore.
- Laser Rangefinder provide the most accurate means at a reasonable price and is portable. It would have been a breakthrough product if eModule was based on a laser rangefinder.

How to use a Laser Rangefinder (LR)?

A LR is one tool any Tech Camera users should have. With HPF ring(s) or with printed card(s) for A-S, accurate focus can be made with a one-click distance measurement. Keep the picture of the cards in iPhone, and you will always have it with you. You may get a simple App which provides HFD and Near and Far Focus distance with a measured distance or make a quick spreadsheet. Without any intention of insulting our forum members, it is very important to read manual and go through all functions. Spend an hour with it. I have met too many who have Disto but didn't know it could be in either metric or imperial mode, different decimal points, the location of sensor, front or back assignment of the reference point, etc. I have Disto manual in both iPhone and iPad in PDF format to refresh my memory how to measure the horizontal and vertical distance of a inclined object point.

How to use LensTilt?

SIMPLE LENS TILT
If you are limiting the lens tilt with the 'Plane of Sharp Focus' that is parallel to horizontal ground, and not to tilt the camera, it is easy to find both lens tilt angle and the required focus distance. You can have a simple spreadsheet with only two user input; f and J, and use it in an iPhone. The equations are as follow:

alpha = arcsin (f/J), where alpha is lens tilt angle, f is lens focal length in mm, and J is the vertical distance between lens axis and your Plane of Sharp Focus in mm.
Fd = J / sin(alpha), where Fd is the calculated focus distance in mm.

If you are focusing the ground plane, J is the camera height from ground; if you are focusing on items on horizontal table top, J is the vertical distance between the lens axis and table top; if you are focusing on the street below from rooftop, J is the vertical distance between lens axis and the street, etc.
J is always located vertically along the lens nodal point.

It should be noted that the conventional concepts of DOF or HFD do not apply once a lens tilt is made. DOF is not two parallel planes from the lens anymore but a wedge (above and below the Plane of Sharp Focus).
HFD also lose its relevancy and I will explain it using examples:
- SK35 at 8.0 aperture and CoC setting of 3 pp of P45 (0.02mm)
- Ground to be the plane of Sharp Focus

- If Camera Height is 1 meter, Tilt angle is 2.1, Focus distance is 29.6 meter and HFD is 8.1 meter
- If Camera Height is 1.5 meter, Tilt angle is 1.4, Focus distance is 68.8 meter and HFD is 8.1 meter

TILTED PLANE OF SHARP FOCUS
If you want to have the Plane of Sharp Focus in angle to the ground (to have small cactus flowers in foreground and tall cactus tree in the back in focus) without camera tilt, the calculation become more complex. You have to have several more user input for tilted Plane of Sharp Focus; vertical and horizontal location of both Near and Far Object relative to the Lens Nodal Point. And J is not anymore the vertical distance between the lens axis and the ground and will be calculated based on the locations of Near and Far Object.

TILTING CAMERA
Tilting the camera in addition to the lens tilt makes geometry even more complex.

What is 'Lens Equation'?

A "lens equation' will translate the measured object distance into the distance between the lens nodal point and the sensor plane for a specific lens. In place of 'lens equation', ALPA provides HPF rings and A-S provides the helical focus ring and lookup tables and both work 'good enough'. It is an industry convention that the object distance is between the sensor plane (not the nodal point) and the object. The equation can be developed with the data provided by manufacturers (ALPA and A-S) or with your own calibration data.

It streamlines the workflow using 'calculation' on an iPhone, more accurate without 'mental' interpolation, and provide a means to enhance the usability of HPF ring with a simple modification.

Jae M
 
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jlm

Workshop Member
more power to you, Jae

i would buy your app and i do place value on software, and in addition, you know the value i place on hardware;)
 

PeterL

Member
I'm speaking as someone who has developed and sold (with limited but some success) an iOS app, I think you've underestimated the potential of the iOS sales. People are not going to put up $125 for something they do not know will work for them or not, and there is no way to test it. Don't get me wrong, I'm sure your app is great and works as advertised, but the above is unfortunately the scenario you have to live with in in the iOS world. Why not make it available for $9.99 for a few weeks and see what happens, you may be surprised and have nothing really to loose......

Just a thought.

Cheers, -Peter
 

PeterL

Member
One thing you didn't consider is the other important issues I described, very small target market. I am almost positive that a great majority of existing user base (500) will buy $10 app, and exhaust the market, netting me a couple thousands dollars. I didn't say it but $125 does not make a viable venture.

Jae M
Well - the price of $125 was actually my point - it will not work for an iOS app. I still think you completely underestimate the potential scale of the market. Many people are interested in this stuff, as pointed out by Guy - the DSLR market is huge. At $10 (or less) you can tap into this and by economy of scale you will be surprised how quickly things add up. This is my experience, I initially also thought the target market was too small, but was proven wrong.....

Good luck with it.

Cheers, -Peter
 

Guy Mancuso

Administrator, Instructor
Actually I would design it first for the Nikon/canon crowd at the 9.99 rate than within the marketing of it mention the 125 rate for high end technical cameras. Let the big market feed the small market. Just a thought
 

Geoff

Well-known member
There is some good advice here - an app for $125 aimed at the tech camera market is a tough sell. Not because the product isn't worthy, but rather that market is more of a "can do myself" group of modest size who can be quite stingy. For example, consider Rodenstock's DOF calculator - a modest seller to this group at $30.

OTOH, aiming for the larger market for less $ but for more sales might open up the doors: you may achieve a critical mass, where the product becomes known and shared. You might be very surprised - yes, its a different model, but its the new world. Think Canon instead of Sinar. Keep the little bits that the tech camera people need, and you might have a win-win. Again, what have you got to lose?
 
There is some good advice here - an app for $125 aimed at the tech camera market is a tough sell. Not because the product isn't worthy, but rather that market is more of a "can do myself" group of modest size who can be quite stingy. For example, consider Rodenstock's DOF calculator - a modest seller to this group at $30.

OTOH, aiming for the larger market for less $ but for more sales might open up the doors: you may achieve a critical mass, where the product becomes known and shared. You might be very surprised - yes, its a different model, but its the new world. Think Canon instead of Sinar. Keep the little bits that the tech camera people need, and you might have a win-win. Again, what have you got to lose?
yes, what have you got to loose? the app is already finished, or at least almost - as far i understood.

regarding the price point: $125 is a lot of money for an iphone app.
don't want to depreciate your work, i'm sure it's very useful and you did a good job, but for about $140 i can purchase lightroom4 which has a whole lot more functionality and a lot more hours of usage in my workflow. the percentage of tilted images per year will never reach 100% but every picture runs through lightroom...
okay, the market is a whole lot bigger for adobe, than for your app, but considering the much bigger development investment and running the whole department of the lightroom team is also much much more cost intensive.

and the fact that it's not possible to get trials of ios software can't be denied.

for my workflow, the ability to use the iphone as a viewfinder is not important, i'm happy with my vario finder and it cannot run out of battery during intense use.
considering the various needs of tech cam users may also be a point to keep the entry not too big. maybe providing upgrades to the full usability.
 

Jae_Moon

Member
The topics are going to the direction which was not my intent when I posted my experience stories. I included 'going commercial' to properly end the story, that's all.

I appreciate it very much all your comments on 'business' aspect of the story. But as the title of this thread indicates, Let's talk Technical on Tech Camera, not business models.

Jae M
 

Jae_Moon

Member
Workflow for Lens Tilt (with or without camera tilt) using my method.


As shown in my previous post, I use the combination of RRS rail and clamps to mount both Rm3di and Disto on Cube (actually I have a PhotoClam) to maintain fixed locational relationship between lens nodal point and Disto laser sensor. It is not feasible to measure X, Y location of an object while handholding a Disto. Cube is a perfect tripod head for Tilt since it provide easy pan/pitch adjustment.

1. Select a right focal length lens with selected subject.
2. Roughly frame the image (near and far objects) using whatever method you use (I use Sony RX100 as my optical view finder). Tilt the camera if needed but no tilt of the lens yet. I usually rely on built-in P45 display with roughly estimated focusing just to see if my four edges are properly located.
3. You now fixed the camera height and the camera tilt (if you are using it). Measure and note the camera tilt angle and the camera height.
4. Aim at Near Object point with Disto laser point using Cube's pitch control. Measure X, Y location. Repeat the same for Far Object point.
5. Reset the camera tilt angle that you noted before (so camera is back to the desired composition).
6. Enter the data; camera height, camera tilt angle, camera focal length, near and far object location coordinates.
7. You will have required Lens Tilt angle and the calculated Focus Distance (and Index Setting with Lens Equation)
8. Take picture with proper tilt and focus setting. You will have a pin prick sharp focused image.
9. Since you can see your image very clearly now, you may want to adjust your composition.
10. Many minor adjustments can be done by 'shift R/L and U/D' instead by camera height or camera tilt angle. No adjustments are needed to the lens tilt or focus setting when you do 'shift'.
11. If you decide to use different focal length lens, let say 47mm instead of 35mm to tighten the composition, only thing you have to do is to select other lens in the program. No new measurement are needed. Change the lens, adjust both tilt and focus setting and shoot. You will have another pin prick sharp image.

From step 3 to 8, what I called 'mechanical' part, will take you 2 minutes. You are free to spread your artistic imagination wings to make a masterpiece once the 'mechanical' challenges are overcome. I usually carry my Macbook Pro with me and do tethered shoot while I fine tune the image.


Jae M
 

Jae_Moon

Member
A low Tech but a serious challenge.

My camera equipment is getting heavier and heavier and a mile is getting longer and becoming an uphill as I age. Since I do mainly landscape photo, the challenge is finding a way to pack the equipment safely for the flight and be as light as possible so I can hike 3-4 miles one way without a porter.

I carry Rm3di with three SK lenses and P45. In addition, I have Gitzo Series 3/3-section, Cube, some rails, filters, shade, Disto, and a 13" Retina Macbook Pro, etc. I pack tripod and Cube in a checked-in duffel bag during the flight and carry it on my shoulder while hiking (Cube in backpack).

So I needed a solution to pack Tech Camera and miscellaneous gears and a Macbook Pro 13 in a regular backpack. I wanted to use a regular backpack for its light weight (roughly 2# vs over 8# with camera bags) even though it does not have any serious padding to protect the gears. I decided on Jansport Outdoor series which has fully padded back and comfortable shoulder and waist straps and 3L hydration pack. A laptop can be safely carried in a backpack with a stiff plastic clipboard to protect it from bending force. Now, I needed a case with strong shell to protect the camera, 3 lenses and a DB, and small enough to fit into a regular backpack and does not add much weight. As a weekend 'classical bookbinder' I knew the answer is a case made of Davey Board (a type of paper board for book covers and cases. it is acid free and warp resistant) with stiff foam sheets cut-to-fit lenses and camera. The outer dimension of Rm3di is 8.5"x7.5"x2" and SK90 is 3" tall (SK35 and 47 are shorter) and P45 is 2.75" or so, and diameter of lenses are 3.75".

I made a box with outer dimension of 10"x10"x6.5", with 3 layers of 1.1" foam, cut-to-fit for 3 lenses and a DB, and 2 layers of 1.1" foam, cut-to-fit for Rm3di, inside the box. I covered it with goat skin leather, for look and the added structural strength. It fit snuggly inside the main compartment of Jansport, and Macbook goes next, and miscellaneous stuffs go in additional compartments.

The box with camera, lenses and DB weighs 9#. I put the shoulder strap that A-S provided with camera on the box, just in case I have to check in the backpack with small regional airlines so I can carry it with me along laptop, so far no need for that.

Now I can go places where I want to shoot more easily. I may have to come up with other solution in next 10 years; as I say, it get heavier and heavier.


Jae M















 

Marlyn

Member
Jae,

Thank you for posting this valuable information.

is this 'Lens equation' available anywhere for calculating it all when the camera is tilted. would love to play with it in excel or similar.

Personally I have focus nailed pretty well for level camera, and tilt for most of what I do, but soon as i point the camera down at the subject, ability to focus goes out the door !. (note, I use a Cambo).

Regards

Mark.
 

Jae_Moon

Member
Jae,

Thank you for posting this valuable information.

is this 'Lens equation' available anywhere for calculating it all when the camera is tilted. would love to play with it in excel or similar.

Mark.

Please PM me so we can discuss.

Jae M
 

malmac

Member
Jae


this is an interesting thread - while I don't have a tilt/swing lens for our medium format gear yet, we do have a Canon 24mm T/S lens - so I have been working on understanding the principles. Threads like this have been a help - so thanks.


Mal
 

Jae_Moon

Member
Jae


this is an interesting thread - while I don't have a tilt/swing lens for our medium format gear yet, we do have a Canon 24mm T/S lens - so I have been working on understanding the principles. Threads like this have been a help - so thanks.


Mal


Mal:

Thank you. I do also have Canon 5D2 but no tilt lens. I was alway wondering how the high quality LiveView (such as Canon) would fit into the workflow that involves Lens Tilt or Camera Tilt. Have you tried to visually focus using the LiveView for the simple lens tilt (no camera tilt and focusing on horizontal plane, i.e. the ground)?

I have P45 (no LV) and have been reading that the LV of IQ1 series are not 'there' yet. I am wondering if the high quality LV with CMOS in MFDBs would function as well as the 'bright' GG of the bygone era of 8x10 or 4x5 in overall workflow. I tend to believe that the usability of an on-camera display is not only depending on its resolution but also the size of screen. Maybe the high quality LV on an iPad like device is the solution.


Jae M
 

jotloob

Subscriber Member
Jae

I hope , my question belongs into this thread .
Looking at the LINHOF TECHNO and the ALPA as example . ( can't say anything about ARCA , CAMBO , SILVESTRI , SINAR and others )

The TILT/SWING axis for the TECHNO goes right through the center of the lens .
This is IMO a big advantage for focusing .
With the ALPA , the TILT/SWING axis is either at the bottom or the side of the lens mount to the camera . That makes focusing more difficult .

How do these technical differences influence your Scheimpflug calculations , if at all ?
 

malmac

Member
Mal:

Thank you. I do also have Canon 5D2 but no tilt lens. I was alway wondering how the high quality LiveView (such as Canon) would fit into the workflow that involves Lens Tilt or Camera Tilt. Have you tried to visually focus using the LiveView for the simple lens tilt (no camera tilt and focusing on horizontal plane, i.e. the ground)?

I have P45 (no LV) and have been reading that the LV of IQ1 series are not 'there' yet. I am wondering if the high quality LV with CMOS in MFDBs would function as well as the 'bright' GG of the bygone era of 8x10 or 4x5 in overall workflow. I tend to believe that the usability of an on-camera display is not only depending on its resolution but also the size of screen. Maybe the high quality LV on an iPad like device is the solution.


Jae M


Jae, this image was taken with 5D2 with 24mm T/S lens at about f7.1 with the camera tilted and a few degrees of lens tilt.

I used live view to get the focus at a balanced sharpness - though I did compromise a little because the camera was only about 12 inches from the back of the bike - so perspective was quite extreme. In the original image you can read all the lettering on the instrument panel including the milage. So the lens did a pretty good job from where I sit.

I never use the LV on the IQ180 back - I use the focus mask and do the shoot, check focus mask then zoom in to test for focus accuracy. Apart from the time spent to zoom and check the screen is absolutely reliable in telling me if I have nailed the focus or missed by even a small amount.


Mal
 
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