Ultra Digital XPan - Part 2

In the last post I introduced my 'Ultra Digital XPan' set up, which looks like this in portrait mode:

 

Using my geared head, on a good tripod, gives me solid positional control over composition. To complement the internal levelling guide in my Canon R, I've added a three axis cold shoe bubble level. Finally, I use my H&Y Revoring filter holder, to handle my 82mm filters, thus allowing me to add front filters, for example, on my 720nm IR converted RP I can add a 830nm cut filter.

As mentioned in the previous post, using dual shifts, in conjunction with the Magic Shift Converter optics, I can realise shifts of some 62mm, ie over 30mm in each direction.This allows me, as shown in the last post, to create 4:1 near parallax free captures. I say near, as the lens does move relative to the camera on one of the adapters. 

The resultant stitched image being equivalent to a single image being taken with a sensor that is 98mm x 24mm.

In this post I will discuss using the set up, in the field, in 'true' XPan aspect ratio mode; that is seeking to maximise the pixel capture. 

To achieve this, as shown in the picture above, the camera is placed in portrait capture orientation, to ensure a 36mm sensor height, compared to an XPan negative of some 24mm.

As I was feeling lazy, the test subject is a view 50m from my house. I was using my Canon R and my 80mm Mamiya 645 lens.

Having explored the exposure extremes with my camera's histogram, ie shifting across the full shift range, setting focus and aperature (f/11 in this case), I took a seven image pano bracket set that looks like this:

The two extreme captures represent the 10mm shifting using the Magic Shift Converter, whilst the other captures cover the physical 30mm shift of the Kipon 645 to EF shift adapter, with the MSC at zero. The Kipon shift then ends up as 30*1.4 mm after passing through the MSC adapter’s optics.

After preprocessing in Lightroom, using DXO  PureRaw 5 in this case, I processed the pano bracket set using Lightroom’s Photo Merge, using Perspective projection.

This resulted in a 16165x6782 image, equivalent to a 86x36mm sensor, ie larger than a classic film XPan negative, of 65x24mm.

After cropping the image to an XPan format (65:24), the final, digitally mounted, image looks like this (greatly scaled here because of its size):

To give a feel for the details, here is a 1:1 screen capture of a part of the image:

As far as I'm concerned the experiment has been a great success and I'm content I've got a usable digital XPan-like set up, albeit using medium format Mamiya film lenses and sensor bracketing.

As usual I would welcome any comments on the above or any of my posts. 

 

Ultra Digital XPan - Part 1

If you have been following this blog, you will know I like to ‘play about' with adapters; especially those that allow me to capture images for perfect flat stitching in post.

In previous posts, for example here, I have discussed the Laowa Magic Shift Converter and illustrated its potential when coupled to a Canon TSE 24mm Tilt/Shift lens.

In this post I'll discuss a more flexible arrangement, that allows different focal lengths to be used.

The lenses I've explored are from the Mamiya 645 family, ie 35mm, 45mm, 80mm and 150mm. Although I've dropped using the 35mm as, unfortunately, I seem to have a bad copy, with one side of the image rather distorted, compared to the other side.

In this test I used the 45mm Mamiya 645 lens.

The  camera set up I used loks like this:

That is: a Canon R, coupled to the Laowa EF to RF Magic Shift Converter, coupled to the Kipon 645 to EF shift adapter, coupled to my 45mm Mamiya 645 lens. With this arrangement my total shift is of the order of 50mm, ie 25mm in each direction.

Of course the MSC transforms the 45mm focal length into about a 63mm lens.

Having set up the composition, checked the exposure over the shift range, set focus and aperature (f/11 in this test), it was a simple matter to capture 5 images:

• Kipon +15mm + MSC 10mm
• Kipon + 15mm + MSC 0mm
• Kipon 0mm + MSC 0mm
• Kipon -15mm - MSC 0mm
• Kipon -15mm -  MSC 10mm

Once captured, the five images were processed and Pano mergered in Lightroom. The resultant (flat stitched) pano was 18636 x 4664, ie just short of 87 mega pixels.

This is achievable because of the optics in the MSC, which expands the Kipon’s 30mm physical maximum shift by 1.4.

At the Canon R's pixel pitch of 5.34 microns, this is like using a camera with nearly a 100mm x 24.9mm sensor, ie 36 + 30*1.4 + 20. Graphically looking like the comparison below: where the red rectangle represents a normal full frame sensor, and the blue the 'Ultra Digital Xpan' created with the above set up.

As for the test image, it looks like this (scaled to display in the blog). The 35mm full frame, horizontal, field of view equivalent is similar to a 23mm focal length:

So, I think, finally, I've found my ideal digital XPan set up. If I want to create an ultra wide, 4:1, flat stitched, pano I can use the MSC with the Kipon shift adapter, converting my Mamiya lenses into a 49mm, 63mm, 112mm, 210mm set . If I only want to emulate an XPan aspect ratio, I would replace the MSC with a simple EOS to R adapter (which I have), allowing me to shoot at 45mm, 80mm and 150mm (as my 35mm is not really useable). Finally, with the MSC arrangement I could also shift in two directions using the Kipon and MSC in combination, ie to create various medium format equivalent aspect ratios.

As usual I welcome any comments on this post or any of my posts.

 

Digital XPan field report

In previous posts I’ve covered various ways to sensor bracket, and how to create a digital XPan DNG, by flat stitching a pano equivalent of a 65x24mm film negative. 

In this post I’m simply going to show a few test shots that I just took with my Mamiya 645 45mm medium format film lens, attached to my Canon IR converted RP, via one of my Fotodiox, +/- 15mm, adapters (use the link on the right to explore the various adapters that Fotodiox have).

As usual I first used one of my iPhone Apps to help me with framing, in this case the ViewFinder Mk 2 iPhone App: https://www.artistsviewfinder.com/

In the above we see three of the lenses I have.

Another App I use is the Viewfinder Preview: https://viewfinderpreview.opticalaberration.com/

Post processing was carried out in Lightroom and Photoshop. 

In this particular case, I decided to process the images in black and white. Two were processed at an XPan size, ie shifting in landscape mode, and one in a medium format 5x7 size, ie shifting by +/- 15mm in portrait mode.

To show off the images on line, I digitally mounted them using the DBW plugin, that you can purchase from here. 

I hope this short post has piqued your interest in sensor bracketing and camera format shifting. If you can’t afford an XPan or don’t wish to get into film photography, using a second hand medium format lens and a format adapter, is a great digital alternative.

As usual, I welcome any comments on this post or any of my posts. 

 

Double Adaption: for ultimate control in creating a ‘digital XPan’

Those that have been following my recent posts will know that I've been experimenting with sensor bracketing, and, in particular, the 'best' way to simulate a digital XPan, using one of my Canon RF or EF-M cameras (either visible or IR) and various adapters, eg see the Fotodiox site for examples of the many adapters you can get.

In this post I'll be looking at the benifits of double adaption. That is using more that one adapter.

As discussed previously, using Mamiya 645 lenses, with a larger image circle than the Canon RF format, allows one to exploit shift, and one might be tempted to opt for a single adapter, such as the Fotodiox Mamiya 645 (M645) to Canon RF Shift Adapter:

This adapter allows some 30mm of shifting (+/- 15mm); which initially looks great, until you factor in the Mamiya lenses.

As an example, lets look at the 35mm Mamiya - Sekor C f/3.5 N that I have (#107008):

Like all/most Mamiya 645 lenses, the infinity is at a hard, mechanical, stop, and my experience is that infinity can be slightly thrown out when coupled with adapters. In theory one could try and adjust the lens for a more accurate infinity with an adapter, however, this could end up as a wasted effort if you are using different adapters, as each adapter may be a few microns adrift from each other because of manufacturer’s design, quality control and tolerances.

This is where double adaption comes in.

The first adaption is to introduce a shift adapter to go from a Mamiya 645 lens to a Canon EF mount, then add a focus correction adapter to go from EF to RF. The adapters I have used are the Kipon Shift M645 - EOS, and the Fotodiox dlx Stretch EF - EOS R.

 

As can be seen, the additional advantage of using the EF - RF stretch is that it comes with rear, drop in, magnetic ND filters (ND4, 8 and 16). The final double adapter set up looking like this:

Using this arrangement of adapters allows me to capture a 61.75 x 24 mm, stitched, flat, panorama, using my visible band R or my IR (720nm) converted RP. That is creating a digital XPan image, albeit by using a medium format Mamiya film lens, rather than an XPan film lens. 

The in field workflow I've come up with goes like this:

• Set the Mamiya on its widest aperture, eg f/3.5 for my 35mm lens;
• Calibrate the lens for infinity by putting the lens at infinity, ie zooming in to the farthest point of interest in the image, and adjust for maximum focus at that point, using the stretch adapter;
• Set the required aperture (I tend to use f/16 or f/22 for maximum depth of field, and correct for diffraction softening in post) on the lens and the exposure time, using the histogram and ETTRing;
• Ensure the ETTR exposure covers the shift extremes;
• To ensure maximun pano blending success, I personally take three images, ie at the two extremes (+/- 15mm) and one in the middle with zero shift.

As for post processing I find the following workflow creates what I'm looking for:

• Ingest into Lightroom;
• Use Raw Detail to clean up the images;
• Use pano photo merge;
• Use Topaz AI, including, if required, dust and stratch (although this is now available in Photoshop ACR and hopefully will be in Lightroom soon) and Topaz Superfocus, to tidy up any diffraction softening;
• Tone and finish as required.

The following test shot was taken with the 35mm Mamiya at f/22, and I've zoomed in to show the detail that I obtained. The Image was taken with my IR converted RP and the final image is 10772 x 4217, ie 61.7mm x 24.2mm, and left in RGB space:

The bottom image above is a screen grab from a 1:1 zoom, to illustrate the details.

For completeness here is the B&W version, which I prefer, as colour integrity can be a challenge when post processing IR captures in colour:

I'll wrap up this post at this point as I think I've covered everything I wished to discuss. The bottom line being that double adaption is a viable way to ensure infinity focus on a manual MF lens when sensor bracketing. For me, knowing I can simulate an XPan with my mirrorless digital camera is fun and, I hope, will turn out to be worth while.

As usual I welcome any comments on this post or any of my posts. 

A New Lens for sensor bracketing

Keeping with the theme of sensor bracketing, I thought some may be interested in a new lens I've just got: a Laowa 15mm f/4.5 Zero-D Shift: link here 

As the name of the lens implies, this is a shift lens and is fully manual, ie there is no electronic coupling to the camera.

The shift direction is fully selectable and shifting is achieved by rotating a ring on the lens. The shift mechanism is rock solid and a joy to use. 

The amount of shift is +/- 11mm, thus, using my full frame Canon R or full frame IR converted RP, allowing the creation, in post, of an image as if it was captured by a 58mm x 24mm or, by shifting vertically, a 36mm x 46mm sensor.

For the greatest flexibility I decided to purchase the EF mount version, so I could couple this to my RF format cameras or EF-M cameras by one of the many EF to RF or EF-M adapters I have.

To show the pano capability, here is a test image taken with the visible band Canon R. In this example creating a 10285 x 4225 pixel image:

This second test is a non-shifted IR capture, cropped to a square format:

So far the experience with the lens is good. It is solidly built and appears to be of good quality, and the shift mechanism is a joy to use. The only 'downside' being the bulbous front lens, which I will need to be carefull with.

As usual I welcome any feedback on this post or any of my posts. 

 

Another look at Sensor Bracketing: Part 3

In the last two posts (here and here) I discussed what I call 'sensor bracketing', that is exploiting a lens with a larger image circle, to allow moving the sensor relative the lens, without parallax or vingetting. In this way we can emulate larger sensor formats, say, like the Hasleblad XPan with it's 65x24 film size, via rectilinear pano merging in post.

Up until now, I've discussed exploiting my Canon 24mm Tilt/Shift lens, including the addition of extra shift via the Laowa Magic Shift adapter. 

In this post I'll be looking at how one can set up a digital 'XPan' using secondhand medium format lenses and manual shift adapters.

Let's first remind ourselves what the Hasselblad 65x24mm XPan film camera looks like, which is not manufactured any more, but remains expensive to buy on the secondhand market:

As for lenses, you can get three native primes for it, 30mm, 45mm and 90mm: shown below with the viewfinder that comes with the 30mm lens.

To emulate the above in a modern, full frame, digital, mirrorless camera, the Canon R or IR converted RP in my case, we need to first substitute out the XPan lenses. I decided to do this with Mamiya 645 lenses.However, the only Mamiya lens that matches the XPan’s primes is the Mamiya 45mm, I therefore needed to accept being 'close enough', by using the 35mm and 80mm Mamiya 645 lenses. Additionally, I also have a 150mm Mamiya 645 lens, which has no XPan equivalence.

To connect the Mamiya lenses to my Canon RF mount cameras, I decided on a Fotodiox shift adapter that has a foot, so that I can keep the lens stationary, allowing the camera to shift relative to a static 645 field of view. The adapter allows a +/- 15mm shift, ie 30mm, no parallax, total shift.

Pulling the above together with a few other gadgets, one version of the set up looks like this (note you don't need the pano rotator or the Canon R cage):

As for capturing two pano brackets, ie at + and -15mm, the biggest problem to address is the lack of a viewfinder. To overcome this, I make use of the Mark II Artist's Viewfinder, which you can download from here.

This iPhone App allows you to set up virtual cameras, so, in my case, I've set up a 35, 45, 80 and 150mm virtual XPan, with a 65mmx24mm sensor. This set up allows me to explore compositions and assure myself that the shifted frames will cover the scene of interest.

As an example, here is what the Artist's Viewfinder shows of a simple test scene:

Here we see all four lenses displayed within the digital XPan format, however, you can then zoom in on the focal length of interest  

As for the final image, here is an 80mm capture (with a field of view close to the XPan's native 90mm), taken by shifting the camera +/- 15mm.:

The merged image is 12020x4515 pixels in size, ie equivalent to an XPan's film size of 65x24mm.

So, there you have it, with the use of some secondhand 645 lenses and a cheap manual adapter, you can emulate different cameras: in this case an XPan.

As usual I welcome any comments on this post or any of my posts.

Another look at Sensor Bracketing: Part 2

In the previous and first post in this short series about 'flat/planar sensor bracketing', I started with one of my best quality lenses: the Canon TSE II 24mm L.

The larger image circle of the TSE lens being exploitable in shift mode, to allow me to add an addition 24mm to the horizontal capture, thus creating a final, flat/planar, stitched image equivalent to using a sensor of 50x24mm. As was said before, not quite an XPan’s 65x24mm film size, but close. 

In this post I'll add in an additional piece of technology that will allow me to create sensor flat/planar bracketing out beyond the XPan, to some 84x24mm.

The technology I'm adding into the equation in this post is the Laowa Magic Shift Converter (MSC):

The MSC has +/- 10mm of shift, and sits between any Canon EF lens and the Canon R (in my case, ie there are other mount options) Thus, using the MSC, with its additional glass, means the 24mm TSE becomes a 33mm focal length TSE lens, with a field of view close to a 30mm XPan. The MSC also introduces one stop reduction in exposure. 

To explore the limitations of using the MSC with the TSE I restricted myself to looking at shifting both adapters in the same, horizontal, direction, ie I could also have used the TSE to Shift up and down, and the MSC to shift left and right, to create a Medium Format sensor equivalent format, eg [36+(24 or 20)] x [24+(20 or 24)].

In this pano experiment I continued to use the PocketPano frame, to keep the TSE lens stationary, ie only the sensor moved.

As usual, my test scene was my garden and I shifted both the TSE and MSC and accepted vignetting, to see how the software handled things:

After ingesting into Lightroom, I undertook a pano merge, using the perspective option, which generated the following 15830x4684 pano stitch (note, owing to the size of the images, the following are screen grabs):

 

Although I used my geared head and in-camera levelling feedback, clearly I wasn'y quite level.

After a bit of LR toning I ended up with the following image, which, at the Canon R pixel pitch and not being level, is 84.5x24mm equivalent, ie if I had cropped out the edges:

Finally, here is a comparison with a 617 (XPan) size, ie 65x24, showing the ability to adjust the scene in post, without losing the XPan size:

Clearly at the edges one can see the image quality falling away slightly, as you would expect at the edge of a lens; and this can be compared to rotational stitching where we maximise the use of the central region of the lens, albeit at the cost of geometric/transformational stitching/stretching.

So, what can we take away from this experiment with using the MSC adapter with the 24mm TSE?

First, modern stitching software is robust and seems to handle 'capture artefacts', such as vignetting, well, as long as you have sufficient image to image overlap.

Secondly, if you accept the 'cost' of sensor bracketing and stitching, eg ‘static’ scenes,  you can use single and multiple shift adapters to emulate the film area on an XPan and wider; albeit using a TSE lens.

Thirdly, if you 'only' use the MSC you can use any Canon EF lens with your Canon R (plus there are adapters for other combinations) and thus create a 56*24 mm pano, from two captures, ie 10mm left shifted and 10mm right shifted. However, you will observe vignetting, although this is less of an impact when using the 617 central crop. I’ll be writing about using the MSC with EF lenses in a future post.

Fourthly, using the TSE and the MSC orthogonally you can create a 3x3 capture to emulate a medium format sensor, eg [36+(24 or 20)] x [24+(20 or 24)].

As usual I welcome any comments on this post or any of my posts.