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Archive 2016 · Cambo Actus Photographs

  
 
freaklikeme
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p.4 #1 · p.4 #1 · Cambo Actus Photographs


Well, I did it. The DB-2 upgrade kit, along with the ground glass finder and an H-mount adapter is on its way. With the back itself, I'm baby-stepping. I found a gently used Aptus 75 (48x36mm 33MP CCD) that tests well on my buddy's H3D and 35mm lens, so I'm hoping any centerfold issues will be marginal when shifted with the APO-Sironar Digital 45. The lack of micro lenses and the fat pixels should make it a good choice for my older lenses, and there will be enough room in the IC's on my best to use them as single shot PC lenses.


Jun 30, 2017 at 07:26 PM
rdeloe
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p.4 #2 · p.4 #2 · Cambo Actus Photographs


I'm not sure I'll ever follow in your footsteps, but I've enjoyed watching you build this system and am looking forward to seeing where it goes. Thanks for sharing. Rob

Audii-Dudii wrote:
As I've mentioned previously, I have added the 35/f1.4 to the small collection of Sigma Art lenses I use with my Actus and I am very pleased by its performance, an example of which is shown below:
...






Jun 30, 2017 at 09:14 PM
Audii-Dudii
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p.4 #3 · p.4 #3 · Cambo Actus Photographs


rdeloe wrote:
I'm not sure I'll ever follow in your footsteps, but I've enjoyed watching you build this system and am looking forward to seeing where it goes. Thanks for sharing. Rob


As ever, thanks for the kind words about my project(s). For me, tinkering with cameras and using them are two very different (but equally enjoyable) hobbies and I can't imagine ever doing only one and not the other!

If you don't mind my asking, I'm curious about why you choose to switch to Fuji from Sony. I ask because I did the opposite and switched from Fuji to Sony. Of course, I was using an X-Pro 1 and X100S when I did so, so the appeal was not only the larger sensors -- I prefer to photograph with wide-angle lenses and the APS-C format can be quite a challenge in that respect, especially when one also wants movements -- but also the larger files they generate.

Going the other way, however, puzzles me somewhat and I am curious as to why you did so. I followed the link to the article you posted on your website -- well done, btw! -- but it didn't really address the rationale behind your project.

Thanks in advance for any additional info you can provide!

(Actually, upon reflection, please don't post your answer here, as this thread has been derailed somewhat already, but post it in your thread about your adventures in tilting and shifting ... thanks!)



Jun 30, 2017 at 10:34 PM
rdeloe
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p.4 #4 · p.4 #4 · Cambo Actus Photographs


I thought I covered that in my web site posting so I double-checked. I think I covered the reason it in some depth. In a nutshell, I needed small, light, high quality for printing -- and I got all that with an X-T2, tilt-shift adapter and OM lenses. http://www.robdeloephotography.com/Pages/Tiltshift-on-APSC To put it in perspective, four OM lenses and the t/s adapter weigh just over 1,000 grams! Perhaps send me a PM if you have specific questions that I didn't answer.


Audii-Dudii wrote:
As ever, thanks for the kind words about my project(s). For me, tinkering with cameras and using them are two very different (but equally enjoyable) hobbies and I can't imagine ever doing only one and not the other!

If you don't mind my asking, I'm curious about why you choose to switch to Fuji from Sony. I ask because I did the opposite and switched from Fuji to Sony. Of course, I was using an X-Pro 1 and X100S when I did so, so the appeal was not only the larger sensors -- I prefer to photograph with wide-angle lenses and
...Show more




Jul 01, 2017 at 10:27 AM
Audii-Dudii
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p.4 #5 · p.4 #5 · Cambo Actus Photographs


This afternoon, I had a brief opportunity to play with my friend's 15/f2.4 Irix Blackstone lens. Unfortunately, he left me only the lens and not a Canon body as well, so I was stuck using it with the aperture wide open.

I mounted it on my Cambo Actus, because I have a dumb Canon EOS lens board, whereas my modified Cambo WDS is permanently setup for a Nikon mount.

I was favorably impressed by the potential of what I saw, starting with the fact that the lens hood is removable and not permanently attached.

Unfortunately, with the lens hood attached, there was very little image circle available for any rise / fall / shift movements.

But with the lens hood removed, there was approx. 5-6mm of rise / fall / shift movement available with the lens focused at infinity and, I suspect, once the lens is stopped down further, this will increase by possibly another few mm still, so potentially there is 7-9mm available under more typical shooting conditions.

This is plenty for my purposes because I'm only looking to correct perspective when photographing architecture and not to stitch ultra-wide angle panoramas.

As the reviewers have reported, the vignetting was significant at f2.4 and even worse with movements applied, but this should also improve as the aperture is stopped down and as most of my photography is done at night, it's not a significant issue for me.

Center shaprness was at least very good, approaching excellent, and although the corners were a bit soft, I expect this to improve with the lens stopped down further.

So this lens is definitely a legitimate option for Actus users looking for an ultra wide-angle lens and needing only a modest amount of rise / fall / shift movement capability.

Overall, I was very impressed with the results from this very limited trial and once I sell some surplus gear I have on hand, I will likely buy a Nikon mount version and give it a more extensive trial.

I am now very much looking forward to having a chance to try the 11mm/f4 version that another friend of mine has on order and expects to receive sometime soon.

P.S.: I will post photos once I have a chance to test the lens again at a proper working aperture (i.e., f5.6 - f11) or I buy one of my own and have spent some time with it.



Jul 28, 2017 at 08:29 PM
genji
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p.4 #6 · p.4 #6 · Cambo Actus Photographs


Audii-Dudii wrote:
Here's one from last night's outing:

http://www.canyonero.com/files/1494860566.jpg

A7R / Cambo Actus / Sigma Art 24-35/f2

I believe this is the first photo I've taken where all four movements the Actus offers (swing / tilt / rise & fall / shift) were used.

Alas, I didn't quite nail the swing movement, as there's some softness on both the far left and right sides of the photo. (Fortunately, it's not so visible in this small .jpg version.)

I guess I need to suck it up about the additional weight and start carrying my 7" external HDMI monitor with me again, so I can better see what I'm
...Show more

I just wanted to say how much I admire the ingenuity you have shown in designing, creating, and customizing a set of equipment that meets your photographic needs. However, the beautiful night photographs you are taking are even more admirable. I like them so much.

And now a question. Why is it, in your opinion, that the Sigma lenses you are using have image circles that are so much larger than "necessary" for use on conventional DSLR bodies?



Jul 29, 2017 at 05:45 AM
Audii-Dudii
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p.4 #7 · p.4 #7 · Cambo Actus Photographs


Thanks, genji, for your kind words! (Have you seen my latest camera project? For my admittedly very much niche purposes, this camera is an even better performer than the Actus, especially now that I'm applying a small, fixed amount of tilt to increase the amount of DoF for most of the scenes I photograph with it. And I have yet another project in mind using the Cambo WRC-400 as the base camera that should perform even better still!)

Before I answer your question, though, let me note that I'm not an optics expert, so the following is speculation on my part. That said, I do have quite a lot of experience working with with larger formats -- prior to my switch to using digital cameras, I was using a 4x5 and 8x10 view cameras, and prior to that, I also used several different medium-format cameras (as well as since, because I have a medium-format digital outfit built around a Contax 645 body and lenses, too, although I don't use it much these days) -- so I would like to believe it's informed speculation, but it remains speculation nevertheless.

So with that disclaimer out of the way, I believe the reason why certain of the Sigma Art-series lenses have larger-than-necessary image circles is because a key part of Sigma's design approach is to make the "sweet spot" of their lenses as large as possible.

One way of doing this is to design the lens to cover a larger format than necessary and then effectively crop the size of the image circle it projects by using the lens hood to block the unwanted/uneeded light from ever entering the lens. (Note: Allowing non-image-forming to enter the lens and bounce around is potentially problematic and can degrade the performance of a lens, so great care must be used when a lens is designed to avoid these issues.)

As lens reviewers are continuoually reminding us, the performance of most lens designs isn't consistent across the full dimensions of the frame they are capturing. Generally, their center performance is quite a bit better than their edge performance, so by making the image circles of its lenses a bit larger than needed, Sigma has been able to effectively expand the size of their center "sweet spot" and therefore improve the performance of the lens away from the center of the image circle.

In effect, the Sigma Art-series lenses are essentially (mini-)medium-format lenses being used on a 35mm format body, just as many of their APS-C-format lenses are essentially 35mm format lenses. Which also at least partially explains why many of their lenses are noticeably larger and heavier than similar 35mm format lenses from other manufacturers.

In the case of the zoom lens I'm using (the 24-35/f2 zoom), this is likely just a byproduct of designing a zoom lens, because the size of the image circles projected by most zoom lenses will vary across their focal length range. The manufacturers then add baffles to the lenses (which are sometimes quite easy to remove, btw) to reduce the size of the image circles so they just cover the format for which they were designed and don't allow extraneous, non-image forming light to reach the sensor.

Speaking of which, because I use my Sigma lenses without their OEM lens hoods, I have to be careful to avoid veiling flare and other artifacts that can appear whenever non-image forming light is allowed into a lens or camera body. For this reason, whenever it's possible, I use compendium shades and mount them on my camera bodies. I also wear a large hat or carry around with me a piece (or pieces) of black foam-core board that I use to flag the lens as necessary. And sometimes even this isn't enough, so I have to pass on taking some photos.

And thanks -- again! -- for your kind words. I work in a very narrow niche that generally isn't appreciated by many viewers, so it's always nice to hear that my photos resonate with at least a few of them.

P.S.: Although I haven't bothered with putting up a website, I do have a photo-blog where nearly 1800 of my (mostly nighttime) photos have been posted over the past eight years. Check it out!



Jul 29, 2017 at 08:07 AM
genji
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p.4 #8 · p.4 #8 · Cambo Actus Photographs


Thanks for your comprehensive reply (as well as apologies for my tardy response). Your theory that "certain of the Sigma Art-series lenses have larger-than-necessary image circles... because a key part of Sigma's design approach is to make the "sweet spot" of their lenses as large as possible" makes perfect sense to me. But, that then raises another question. By employing shift, swing, and tilt to make your photographs, aren't you then moving out of the sweet spot into the less satisfactory region that Sigma has deliberately "masked"?

More importantly, I'm really glad I asked my original question because it prompted you to link to your photo-blog. Wow! What a wonderful body of work. You say that you work "in a very narrow niche" but I'm a firm believer that the further one travels along a narrow path the wider it becomes. I'm going to start with the first picture (28 November 2009) and work my way forward.



Aug 01, 2017 at 12:14 AM
Audii-Dudii
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p.4 #9 · p.4 #9 · Cambo Actus Photographs


genji wrote:
Thanks for your comprehensive reply (as well as apologies for my tardy response). Your theory that "certain of the Sigma Art-series lenses have larger-than-necessary image circles... because a key part of Sigma's design approach is to make the "sweet spot" of their lenses as large as possible" makes perfect sense to me. But, that then raises another question. By employing shift, swing, and tilt to make your photographs, aren't you then moving out of the sweet spot into the less satisfactory region that Sigma has deliberately "masked"?


Yes, no doubt I am. But as you've noticed, most of my photography is done at night, so a diminution of image quality around the outside edges usually isn't apparent, hence not an issue. However, on those rare occasions when it is an issue, I can simply switch to using my Contax 645 lenses instead, which project much larger image circles and do so without sacrificing much in terms of center sharpness and resolution.

More importantly, I'm really glad I asked my original question because it prompted you to link to your photo-blog. Wow! What a wonderful body of work. You say that you work "in a very narrow niche" but I'm a firm believer that the further one travels along a narrow path the wider it becomes. I'm going to start with the first picture (28 November 2009) and work my way forward.

Again, thanks for the kind words about my photos! Note that I tend to use my photo-blog as a scratch-pad of sorts, so not every photo I post there is great art. Not even close, in fact (although one can certainly wish, eh?)

But I do hope you enjoy them regardless!



Aug 01, 2017 at 03:43 AM
Audii-Dudii
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p.4 #10 · p.4 #10 · Cambo Actus Photographs


As yet another data point, I borrowed a friend's Pentax K-1 body and Zeiss ZK 35mm/f2 lens the other day to experiment with it. While there are many things to like about the K-1, overall, I quickly determined that it isn't the right camera for me and the type of photography I do.

Out of curiosity, I held the Zeiss lens in front of the lens mount on my Cambo Actus to determine exactly how large of an image circle it projects and to my surprise, it appeared to be large enough to allow for 8-10mm of rise / fall / shift movements.

So I ordered a Pentax to Canon EF lens adapter from Amazon for same-day delivery and, sure enough, the image circle is indeed as large as I thought it was.

Early this morning, I used it for a photo outing to the downtown Phoenix historical warehouse district, where I took this photo:



I used 10mm of rear fall to compose this photo and stopped down to f8. If I look closely enough, I can see a bit of softening in the upper lefthand corner and about half that amount of softening in the upper righthand corner. But for my purposes, this isn't a significant issue, because the corners of most of my photos are in dark shadow areas, if not out-and-out blackness, and there are few visible details to go soft!

I've been a life-long fan of Zeiss lenses and prior to switching over to my trio of Sigma Art lenses earlier this year, I've been using them since the early 1990s. Fortunately, my friend has four more Zeiss ZK lenses on hand, plus three Pentax FA Limited lenses, and he's agreed to let me borrow all of them for a week or two to see how they work on my A7R / Cambo Actus combo. Stay tuned!



Aug 08, 2017 at 06:17 PM
genji
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p.4 #11 · p.4 #11 · Cambo Actus Photographs


Audii-Dudii wrote:
As yet another data point, I borrowed a friend's Pentax K-1 body and Zeiss ZK 35mm/f2 lens the other day to experiment with it. While there are many things to like about the K-1, overall, I quickly determined that it isn't the right camera for me and the type of photography I do.

Out of curiosity, I held the Zeiss lens in front of the lens mount on my Cambo Actus to determine exactly how large of an image circle it projects and to my surprise, it appeared to be large enough to allow for 8-10mm of rise / fall /
...Show more

I misread the last paragraph of your post and thought you'd decided to give the K-1 a second chance but now I realize that it's the Zeiss lenses you're actually interested in. Out of interest, why isn't the K-1 the right camera for you and the type of photography you do?



Aug 09, 2017 at 01:03 AM
Audii-Dudii
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p.4 #12 · p.4 #12 · Cambo Actus Photographs


Basically, there are two reasons: 1) The K-1 has a mirror box, which means it cannot be used with 35mm-format lenses on my Cambo Actus or modified Cambo WDS cameras (its flange-to-sensor distance is too short), hence it will require medium-format lenses be used instead; and 2) as with most DSLRs, its Live View implementation sucks compared to just about every existing mirrorless camera. I'd also hoped that its true-color ability (i.e., rendering each pixel as RGB without Bayer pattern demosiacing) would result in better B&W conversions, but the difference isn't significant or at least not that I could see.

Finally, it's a lot bigger, heavier, and IMO, less ergonomically friendly than my A7R, so there's nothing for me to gain there, either.



Aug 09, 2017 at 01:23 AM
genji
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p.4 #13 · p.4 #13 · Cambo Actus Photographs


Audii-Dudii wrote:
Basically, there are two reasons: 1) The K-1 has a mirror box, which means it cannot be used with 35mm-format lenses on my Cambo Actus or modified Cambo WDS cameras (its flange-to-sensor distance is too short), hence it will require medium-format lenses be used instead; and 2) as with most DSLRs, its Live View implementation sucks compared to just about every existing mirrorless camera. I'd also hoped that its true-color ability (i.e., rendering each pixel as RGB without Bayer pattern demosiacing) would result in better B&W conversions, but the difference isn't significant or at least not that I could see.

Finally,
...Show more

Duh! I'd totally forgotten that the K-1 is a DSLR. And the fact that you're using PK lenses with a Pentax K to Canon EF was a dead giveaway.



Aug 09, 2017 at 01:31 AM
Audii-Dudii
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p.4 #14 · p.4 #14 · Cambo Actus Photographs


Another two samples ... Yes, I think I'm in love with this lens!





With room for 8-10mm of rise / fall / shift movements, its image circle is more than large enough for 98+% of the photography I will ever do with it.



Aug 09, 2017 at 05:51 AM
Audii-Dudii
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p.4 #15 · p.4 #15 · Cambo Actus Photographs


So my very generous friend has loaned me 12 of his Pentax-mount lenses, including five Distagons from Zeiss (18mm, 25mm, 35mm, 85mm, 135mm) and all three FA Limiteds (31mm, 43mm, 77mm), to use with my Cambo Actus and modified WDS cameras for a couple of weeks (and/or to subsequently purchase, should I so desire.)

Here's a photo of the Pentax FA 31mm Limited mounted on the Actus via a modified lens panel (because Cambo doesn't make a K-mount lens panel for this camera):



Yesterday, I did some quick testing to determine the size of the image circles the lenses project, so I could weed out those that came up short from any further testing / experiments.

To my surprise, all five of the Zeiss lenses and all three of the Pentax FA Limited lenses project image circles large enough to provide for at least +/- 10mm of rise / fall / shift movements on the short (i.e., 24mm) side at f8 and focused at infinity! Typically, there is ~2mm less movement available on the long (36mm) side.

In fact, several of them -- in particular the Zeiss 85/f1.4 and 135/f2 lenses -- have image circles much larger than that, even approaching the mechanical limits of the Actus' movements!

(I can't comment on the four remaining lenses because I haven't tested any of them yet.)

Needless to say, I find this all very encouraging, although I can't yet speak to the image quality of any of them (except for the Zeiss 35mm/f2, which I've commented on in another post above.).

More about that later, I'm sure....



Aug 10, 2017 at 01:52 PM
akpo.ca
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p.4 #16 · p.4 #16 · Cambo Actus Photographs


The 135mm Apo-Sonnar and the 85/1.4 Milvus/Otus/Planar will cover 44x33mm medium formats at infinity as well as a tiny bit larger.

Wides usually do not have large image circles, unless they are wide angle zooms or tilt-shift/pc lenses where they were originally designed with a larger IC to accommodate 35mm full-frame shift.



Aug 13, 2017 at 07:47 AM
akpo.ca
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p.4 #17 · p.4 #17 · Cambo Actus Photographs


You have those cheap PK-EOS adapters that slightly put the lens off 12 o'clock right? I have the same one and I'm trying to find one of these adapters that allow the Pentax lens to be put at 12 o'clock on my Canon :/


Aug 13, 2017 at 07:49 AM
Audii-Dudii
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p.4 #18 · p.4 #18 · Cambo Actus Photographs


akpo.ca wrote:
The 135mm Apo-Sonnar and the 85/1.4 Milvus/Otus/Planar will cover 44x33mm medium formats at infinity as well as a tiny bit larger.


Indeed. Unfortunately, I'm much more of a wide-angle kind of photographer, so as much as I enjoy the image quality of these longer lenses, it's highly unlikely I will ever have much use for them given the type of photography I presently do.

Wides usually do not have large image circles, unless they are wide angle zooms or tilt-shift/pc lenses where they were originally designed with a larger IC to accommodate 35mm full-frame shift.

With regard to the collection of lenses I'm presently experimenting with, only the Pentax FA Limited 43mm/f1.8 has so far proved to have an image circle that's too small to be useful for my purposes. (FYI, it's good for only 6-7mm of rise / fall / shift movements along the 24mm side of the frame at f8 and focused at infinity and 3-4mm along the 36mm side, which simply isn't enough to meet my needs. The IQ is quite nice, however. Fortunately, this situation improves somewhat with the FA Limited 31mm/f1.9, as its image circle allows for 8-9mm of rise / fall / shift movement along the 24mm side and 5-6mm along the long side. This is sufficient for probably 95+% of my photos.)

I'm still determining the extent of the usable image circles projected by the other lenses, but so far, I've determined the Zeiss ZK 35mm/f2 is good for ~10mm of rise / fall / shift along the 24mm side and 7-8mm along the 36mm side, which is plenty for me. And the Zeiss ZK 25mm/f2.8 is good for just a teeny bit less than that.

The IQ for both lenses is very good to excellent, however. Here's a photo taken with the 25/f2.8 early yesterday morning:



And one taken the night before with the 35mm/f2:



In both cases, I've applied approx. 5mm of rear fall to crop the foregrounds and no vignetting compensation (in fact, I actually added a bit of vignetting during post-processing.) Although it's difficult to tell from these small .jpgs, the IQ is excellent with both photos.

It's too early to say for certain, but as it stands right now, I think my friend is more likely to be getting a check from me rather than getting either of these two lenses back.

Next up is the ZK 21/f2.8 and needless to say, I'm very much looking forward to this one!

Edited on Aug 13, 2017 at 08:36 AM · View previous versions



Aug 13, 2017 at 08:17 AM
Audii-Dudii
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p.4 #19 · p.4 #19 · Cambo Actus Photographs


akpo.ca wrote:
You have those cheap PK-EOS adapters that slightly put the lens off 12 o'clock right? I have the same one and I'm trying to find one of these adapters that allow the Pentax lens to be put at 12 o'clock on my Canon :/


Actually, I don't know whether the adapter I'm using mounts the lens slightly off-center as it was delivered, because I've added a locking screw and in the process, tweaked the alignment such that the lens is perfectly straight up and down with the aperture indicator positioned exactly at 12 o'clock:



The Canon EOS EF lens mount the previous owner had fabricated doesn't include any sort of lock mechanism, which actually worked out great for my purposes, because this means I can fine-tune the alignment of the adapters I use and then simply drill/tap an M4x.70 hole for a screw to firmly lock both the mount and adapter together and however I want them aligned.




Aug 13, 2017 at 08:33 AM
genji
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p.4 #20 · p.4 #20 · Cambo Actus Photographs


Audii-Dudii wrote:
Indeed. Unfortunately, I'm much more of a wide-angle kind of photographer, so as much as I enjoy the image quality of these longer lenses, it's highly unlikely I will ever have much use for them given the type of photography I presently do.

With regard to the collection of lenses I'm presently experimenting with, only the Pentax FA Limited 43mm/f1.8 has so far proved to have an image circle that's too small to be useful for my purposes. (FYI, it's good for only 6-7mm of rise / fall / shift movements along the 24mm side of the frame at f8 and
...Show more

Looks like it might be time to kick those Sigma lenses to the curb...



Aug 13, 2017 at 10:28 PM
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