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dreifish

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dreifish last won the day on November 15

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About dreifish

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    Manta Ray
  • Birthday 02/10/1983

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    http://www.andreiv.com

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    Finland

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    Canada
  • Camera Model & Brand
    Panasonic GH5
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    Nauticam NA-GH5
  • Strobe/Lighting Model & Brand
    Sea&Sea DS-02
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    Fridge Magnet Films

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  1. The 140mm dome works perfectly with the 8-15 on the a7rii, Simon. I used that combo for a couple of years. Downside is splits are difficult, but for travel and currents, it's a big asset to have the smaller port. The 170mm dome is made for rectilinear lenses, just like the Nauticam 180mm. It's not the ideal option for a fisheye. I'd go with the 140mm + a seperate dome port dedicated for splits. The nauticam 8.5" acrylic dome works fine for that purpose and it's 1/4 the price of the 230mm glass dome
  2. I haven't shot with a rectilinear lens like the 8-18 or 7-14 on the GH5, but my experiences with the 7-14 on the GH4 amounted to the pespcetive distortion being too great at the 7mm end. On the other hand, now that I think back, I shot video with the 16-35mm on A7RII for a while with Nauticam 180mm dome and was overall fairly happy. Never experienced the severe pincushion perspective distortion you see with a 7 (14mm FF equivalent) lens. Now, if I read you article correctly Massimo, the horizontal angle of view of a 16mm (full frame) is more or less the same as the horizontal field of view of the WWL1 at the widest end, right? Maybe that suggests that this is the widest angle of view you can deploy for video before perspective distortion becomes too distracting. I should play a bit more with my 9-18mm olympus lens with GH5 and 180mm dome. If the horizontal AoV is really quite close to the WWL-1 and the rectilinear percepective distortion is under control at 9mm, it does give some advantages over the WWL like being usable for split shots and better reach and IQ at the long end.
  3. Hmm.. interesting observation Massimo. It hadn't occured to me that the fisheye distortion accentuates the WWL-1 diagonal FOV, but I see your point. Still, even if the horizontal field of view of the WWL-1 and 7-14 are roughly equivalent, the WWL-1 for sure produces much more usable results. The perspective distortion with a rectilinear lens at 7-8 MM is very off-putting.
  4. This doesn't accord with Nauticam's claims that the WWL-1 produces a 130 degree diagonal field of view with a 28mm equivalent lens. 28mm = 14mm in m4/3 terms. On m4/3, 130degree degree diagonal field of view with equates to a 5mm rectilinear lens (14*.36 = -surprise-surprise- 5.05). The 7mm end of the 7-14 only has a 114 degree diagonal field of view.
  5. As I explain above, the lack of a native fisheye is entirely negated by the fact that the adapted Canon 8-15 works flawlessly. By pretty much every other manufacturer, you mean whom? Canon and Nikon? Neither of them has such a 'native' fisheye if you look at their mirrorless offerings. Neither does Panasonic for full frame. Maybe a native Sony fisheye would have even faster autofocus, but it's completely irrelevant. I struggle to imagine any scenario where the adapted solution wouldn't be fast and accurate enough. In fact, I'd be willing to bet that if you paired up the Sony A9II with an 8-15 shooting at 20fps, you'd get more in-focus shots in the most demanding action scenario you can envision than pairing the native 8-15 with the Canon 1DXII or the Nikon D5. With all due respect, Adam, this is purely FUD (fear, uncertainty and doubt). Nikon and Canon rely on off-sensor PDAF which is inherently less accurate than on-sensor PDAF or contrast-detect autofocus. Maybe the autofocus was slower on first (and to some extent) second generation Sony A7s, but it has never been /less accurate/ and today there are plenty of tests online demonstrating the A7III, A7RIII, A7RIV and especially A9/A9II get you more in-focus images in action scenarios such as sports than their Canon and Nikon DSLR equivalents. If you still think DSRL autofocus has any advantages over Sony's mirrorless line, your opinion is several years out of date. This is purely speculation that sounds reasonable at a quick read, but is both technically inaccurate and not borne out by real world experience. From a technical standpoint, the simple electronic translation from the Sony control protocol to the Canon control protocol happens in fractions of a millisecond, so while there is objectively a delay introduced, it's completely irrelevant to the total time it takes to focus since actually moving the physical focus elements takes orders of magnitude longer. As for accuracy -- we're talking a completely digital transmission chain. How could the adapter possibly impact the accuracy of the autofocus? To answer your turned-around question, if I was buying an underwater system today purely for photos, I'd probably struggle to choose between the D850 and the A7RIV. I think I'd lean towards the D850 for macro, but the IQ from the A7RIV is superior in my view (more resolution) and for wide angle, the 100% autofocus coverage is better than what the D850 can offer. Not to mention that on-sensor PDAF is more accurate than off-sensor PDAF. If Sony's animal eye-detect ever expands to include fish, it'd be a no-brainer in favor of the Sony for both wide angle and macro scenarios. Right now, only three things weigh in in the D850's favor -- (a) better subject tracking with 3D tracking (this might no longer be true with the latest generation of Sonys, but I haven't tested it), (b) an optical viewfinder, which I prefer for underwater mixed light wide angle photography, (c) base ISO 64 and slightly faster 1/320 flash sync speed for slightly more ability to control the ambient light. Conversly, the Sonys offer (a) more accurate autofocus (no need for autofocus adjustments to lenses), (b) faster frame rates for action, (c) wider autofocus point coverage, (d) higher resolution, and (e) sensor stabilization. But hey.. don't just take my word for it. Backscatter has done an extensive comparison between the D850 and the A7RIII underwater. I think it's safe to say that the A7RIV would have performed even better in things like autofocus. If you bring video into the equation, it complicates things. Then I'd lean towards the Panasonic S1H or the newly announced 1DXIII.
  6. I've used the Sony A7RII (a 2 generation-old Sony) + metabones adapter + Canon 8-15mm for several hundred dives and never had a single thing to complain about when it came to wide angle photos. It had perfectly good autofocus (both fast and accurate) for wide angle and excellent image quality. I'm sure the A7R3 and A7R4 are even better. Prior to that, I used the D800 + Sigma 15mm fisheye for 100-200 dives, and the A7RII + Canon 8-15 was every bit as good or better in terms of both image quality and focusing for wide angle purposes. Not as good for macro focus and focus tracking for macro, but that's a different story. And yes, for wide angle mixed light shots, I do think an optical viewfinder is better than the current generation of EVFs because of the dynamic range it can display. If I was to buy today, I would without hesitation pick the A7R4 over any of the Nikon Z cameras or Canon mirrorless. Lack of a native fisheye option is irrelevant -- the adapted canon 8-15 works so well that it's very hard to imagine how it could be improved upon. The only full-frame camera I would rate as a better purchase for underwater (if only taking photos) would be the Nikon D850. For the record, I have no real skin in this game, as the only underwater setup I currently own is a Panasonic GH5
  7. 1. The color chart isn't necessary. It's there to confirm the accuracy of the technique. 2. The technique as I understand it requires multiple pictures of the same object from different distances in order to reverse-engineer the water filtration factor by comparing the colors of that object (or pixel) from different distances. 3. The advantage over a simple white balance as far as I understand is that it depth-maps all the elements in the picture in 3d space and appropriately color-corrects for all of them depending on the amount of water between that object and the camera. So you'd see warm colors extending far into the background, not just for the foreground subject as you would get with a normal white balance off a grey card at foreground distance. 4. For photos this process is rather cumbersome as it forces you to take multiple pictures of the same subject from different distances. So it will not provide a 1-click adjustment for photos in its current form. 5. For video however, this could be brilliant if your video clip involves movement anyway, as you can get a lot of distance information from subsequent frames of the video (the same way you can get 3d mapping from a moving video clip when doing photogametry). So potentially this could be implemented as a 1-click solution for a video file. Though it would obviously work better raw video.
  8. I think what I sad re: 12-35 was that it wasn't wide enough at the 12mm end . I didn't feel much need to shoot beyond 35mm -- just get physically closer. For my purposes, the 14-42 behind the WWL-1 actually offers a pretty good range. I often end up shooting at the wider end of that spectrum (inherent preference for wide sweeping vistas or reef-level action I guess), but find the barrel distortion to be very mild and totally acceptable. (unlike with a fisheye). I think anything wider would be too much, however. The biggest advantage to wider optics of course is that you can get closer, if the subject cooperates, and still fill a significant portion of the screen with that subject. Even at the 42mm end with the WWL-1 (equivalent to ~30mm full frame FoV, since the WWL-1 is a .36X wide angle converter), I start to find that image quality is lost because of all the water between you and your subject.
  9. I don't see anything in the below videos that would've turned out any differently had the footage been shot in an 8bit codec and the standard or cine-d picture profiles on the GH5, to be honest. There's no real highlight rolloff underwater except in rare circumstances where you're shooting up towards the surface (those shots don't look so natural in this footage, log or not) or blowing out your foreground illumination in mixed-light shots.
  10. At 100 feet even in the most clear of waters, only blue/green/violet light hasn't been filtered out by the water column. No amount of filtration or custom white balance can bring back what's not there in the first place. You'll get much better results selectively lighting part of the subject with strobes.
  11. Regarding the need for red filters on the GH5 for ambient light CWB work: I'm a firm believer that ambient-light CWB only produces 'natural' results down to about 10-12m. Below that, the ambient light color spectrum is just too distorted, an no amount of global filtration or custom white balancing can make it appear natural. Plus, with the GH5, doing a CWB with a red filter below 12m often oversaturates the red channel and you end up with purple water you need to correct later. Down to about 10m, you can set an adequate CWB on the GH5 without a filter. Will you get better results with a red-filter + CWB combination? Not from 0-6m. If you're only shooting ambient light + CWB down to 6m, you don't need to bother with red filters. From 6-12m, you get slightly better results with the red filter since the GH5's CWB doesn't seem to let you go above 10000k/+150 magenta. But it's a subtle difference, not a night-and-day one, and most obvious at the deeper end of the range (where colors start to look a bit desaturated and odd anyway). You probably could compensate for any difference with color correction in post. Keldan makes a red filter that fits in between the flat port and WWL-1 if you use the combination, meaning it can be relatively easily removed or added during the dive. I was experimenting with it on my trips to Tubbataha in June (video will come soon). Unfortunately, in Tubbataha the reef top is usually in the 9-15m deep range, so it's borderline for ambient light shots. But I got some decent results with the red filter and CWB (doing the CWB no deeper than 12m). I wish I had done systematic tests showing what CWB vs. red filter + CWB looks like at 3m, 6m, 9m, 12m and 15m to settle the red filter question once and for all, but I didn't. It'll have to wait till my Red Sea trip in late October I guess.
  12. Yes, this would be the (somewhat pricier) alternative for wide angle. You can use it with the Sigma 18-35F1.8 zoom if you're shooting only in the 4k crop. That would give you a pretty useful range once you account for the 1.7X crop factor plus you could potentially shoot quite wide (F2.8, maybe even F2) because the WACP takes care of most of the corner softness issuess you'd have with rectilinear wide angle lenses. But none of these options give you any sort of stabilization, so that's probably worth keeping in mind.
  13. Price drop -- $1000 each or $1800 for the set + shipping. Located in Finland.
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