Jump to content

Isaac Szabo

Member
  • Content Count

    97
  • Joined

  • Last visited

  • Days Won

    9

Isaac Szabo last won the day on April 7

Isaac Szabo had the most liked content!

Community Reputation

40 Excellent

2 Followers

About Isaac Szabo

  • Rank
    Moray Eel

Contact Methods

  • Website URL
    https://www.instagram.com/isaacszabo/

Profile Information

  • Gender
    Male
  • Location
    Arkansas
  • Interests
    Freshwater photography

Additional Info

  • Show Country Flag:
    United States
  • Camera Model & Brand
    Sony A7R II

Recent Profile Visitors

1153 profile views
  1. The "extreme crop" you posted has been downsized (unless it was shot on an old, low resolution camera), yet its lack of sharpness due to shooting at f/29 is already apparent. It would be even more apparent at the original resolution - especially if you had an f/8 or f/11 shot to compare it to. Please explain what point I'm missing? Like I said in my first post and several others, the loss of sharpness due to shooting at high f stops only matters if the images will be viewed at a large size, and for some people the gains in DOF will trump the losses in sharpness. In other words, I've been saying a version of "there is sharpest, and there is sharp enough" all along. If you prefer the results you get at f/29, there's nothing wrong with that.
  2. Like Chris said, that little silica gel packet hasn't been doing anything for a long time. I think the key reason why you experienced condensation this time is that you didn't pull a vacuum. Decreasing the air pressure decreases the dew point, so pulling a vacuum is most likely the only tool you need to avoid condensation issues. If you want to be sure, you can do a test by closing up your housing in warm, humid air, pulling a vacuum, putting it in a cold environment for a little while, and seeing if any condensation forms inside.
  3. Hi Craig. I'm afraid you've misunderstood. To evaluate sharpness, one needs to view the image at it's original resolution at 100% zoom (actual pixels). Since uploading full resolution images to the internet has its challenges, oftentimes a smaller crop of just the relevant part of the image is uploaded instead (i.e a 100% crop). The key is that the image cannot be downsized if you want its sharpness to be accurately evaluated. The images you have shared have been downsized greatly from their original resolution, and it's not possible to truly evaluate their sharpness at that size. Here's an example. If you compare my 2 feather images uncropped and downsized to web resolution, you cannot see the difference in sharpness: On the other hand, if you compare a 100% crop of the 2 images (again, actual pixels, no downsizing), the loss of sharpness due to diffraction is clear:
  4. I'm not sure why people are getting hung up on the diffraction issue. It's common knowledge. There are numerous sources explaining it on the web, as well as hundreds if not thousands of lens tests confirming it. And if you don't trust them, it's very easy to test yourself. In any case, here's a quick f/8 versus f/22 comparison I just shot. A7R II with Sony 90mm macro. Subject is a feather. Shot indoors on a tripod with no camera/subject movement. All settings the same except for aperture and shutter speed. Identical post processing. This is a 100% crop (actual pixels): For my eyes on my monitor, the difference is dramatic. And yes, I see this same effect with underwater photos. If you can't see the very obvious loss of sharpness/resolution, then you might be using a monitor with too high pixel density. If anyone wants to see the full resolution images, here are links to them: diffraction test f/8, diffraction test f/22. If you don't trust my results, it's easy to do your own test.
  5. Yes, a small pixel pitch (i.e. high pixel density) is worse for evaluating sharpness. Your 32" 4K monitor has a pixel density of only 138 ppi (pixels per inch), which is a the low side. It will be good for evaluating sharpness, though a monitor with a ppi closer to 100 would make it even slightly easier. And yes, when you're using a low ppi monitor like yours, zooming into 200% offers no advantage. Even with high ppi monitors it's a flawed approach (the image is being interpolated, etc). By high resolution (again, in terms of pixel density), I'm talking about monitors with a ppi in the 200+ range. They are very common these days. I have a 15.6" 4K laptop (282 ppi) and an older 15.6" 1080p laptop (141 ppi), and it's impossible to see sharpness differences on the 282 ppi screen that are immediately apparent on the 141 ppi screen. The high ppi screen is terrible for evaluating sharpness. I also have a 27" 2.5K NEC monitor (109 ppi), and not surprisingly it's excellent for evaluating sharpness. Have you ever done a side by side comparison evaluating sharpness at 100% on high ppi and low ppi monitors? If not, give it a try. You may be surprised by the results.
  6. Nice shot! If you want its sharpness to be critically evaluated you would need to share the full resolution image or a 100% crop (not that I'm asking you to go to the trouble of doing that). But like I said earlier, there's nothing wrong with choosing to shoot at f/29 if you value DOF over sharpness for a particular shot or if the image won't be used at a large size. I can see diffraction softening in my underwater images starting around f/11, but I'm a pixel peeper. If you're happy with what you're getting at smaller apertures, then that's all that matters. After all, sharpness isn't the only factor to consider when choosing what settings to use, and increased DOF can be more important for some images.
  7. I realize it can be counterintuitive that a high resolution monitor (in terms of pixel density) makes it harder to evaluate sharpness, but I think this is a simplified way to kind of explain it: the higher the resolution of the monitor, the smaller the images are displayed. For example, an image that is 1920 x 1080 pixels will take up the whole screen of a 1080p monitor but only 1/4 the screen of a 4k monitor. So if you're trying to evaluate the sharpness of an image at 100%, you will have a larger view of the details on a lower resolution monitor and a smaller view of the details on a higher resolution monitor. That's why some people with high resolution monitors resort to zooming in to 200% or more to try to evaluate sharpness (which can help slightly but is still flawed). Anyway, there's nothing wrong with stopping down past the sharpest apertures if you value depth of field over sharpness. I just think it's helpful to be aware of the tradeoff when making that decision.
  8. Diffraction begins to degrade sharpness a tiny bit even at f/8: Source: https://www.ephotozine.com/article/nikon-af-s-105mm-f-2-8g-ed-if-vr-micro-lens-23446 In my real world underwater photos, I can notice the small drop in sharpness from f/8 to f/11, though I still find f/11 acceptable if I want a little more DOF. If some are having difficulty detecting the obvious loss of sharpness/resolution at f/22 when viewing images at 100%, then it could be due to the use of high resolution monitors, which are terrible for evaluating image sharpness.
  9. Stopping down to f/22 significantly reduces sharpness/resolution due to diffraction. If you only ever intend to present the images at a small size, then that doesn’t matter, and the increased depth of field of f/22 can be beneficial. But if the images will be viewed/printed at a large size, then nothing in the f/22 image will truly be sharp, and f/11 will look better.
  10. Most configurations do not require a diopter and do provide full functionality of the macro lens when the EMWL is removed. Unfortunately your Nikon DX system requires a diopter and isn't as flexible.
  11. Sounds good. I would stay at 1/500 if you have enough light. If you notice the ISO getting too high, you can drop the aperture or shutter speed a little.
  12. I have a lot of experience shooting available light. Minimum shutter speed for a high percentage of sharp shots depends on your focal length as well as how fast you and your subject are moving. Without knowing those things, I can say that 1/500 is a pretty safe starting point. For really fast moving subjects you want it a little higher (1/1000 range), or if you and your subject are static you can go lower (1/250 range). As for aperture, my experience is that f/11 is too high for many available light shots and will result in poor image quality from ISO being too high. I would recommend starting out around f/8 if you have bright sunlight or f/5.6 in lower light. And it's always best to periodically review some images at 100% during the shoot to make sure your settings are giving you sharp, high quality shots while you still have a chance to adjust the settings if they aren't working well.
  13. What aperture are you shooting at? The A7S III cannot do AF-C past f/11. Are you in low light environments without a video/focus light? If so, that could be part of the problem. You might be better off setting up the camera so that it only focuses when you press a button to focus instead of letting it try to focus all the time (that's what I would do anyway).
  14. Beautiful shot @Alex_Mustard! Which objective? I think it has already been well-established that the Nikon F 105mm works properly with the EMWL. What would be helpful at this point is more information from Nauticam on which of the other supported lenses work properly and which suffer the most from the focus shift issue. I would certainly consider switching to a different lens if it meant I would get proper functionality with the EMWL. As for the 100% eye crop, obviously everyone has different standards, but to me that sharpness isn’t very good (certainly not rivaling the best wide angle lenses as Nauticam claims). That said, when you factor in the unique abilities of the lens, I suppose it’s acceptable. And of course it would also look better without the upscaling.
  15. There is a lot of information in this thread, but to sum up: Edward Lai of Nauticam admitted there is a focus shift problem with some lenses when used with the EMWL and that they weren't aware of the issue until very recently because they hadn't done the required testing. For my lens (Sony 90mm) it means all shots will have backfocus error if focused using the normal method in which the camera focuses at f/2.8 and then stops down to the shooting aperture to take the shot. However, I stumbled upon a partial workaround for Sony cameras. In AF-C mode the initial focus acquisition is done at f/2.8 (focus shift with the EMWL), but if you keep holding the focus button down after it acquires focus it will stop down to the shooting aperture and refine the focus (no focus shift with the EMWL). So if I use AF-C and let the camera acquire focus and then give it another second or two to keep focusing, I can get accurate focus fairly reliably with the EMWL. It's not a perfect solution though. Having to wait those extra seconds means I miss many shots. Also, with my camera (A7R II) this method only works up to f/8, so I can't stop down further for more depth of field. And even when it focuses accurately it does not live up to Nauticam's claim that the "image quality rivals the best wide angle lenses". Despite that, it can do unique things that other lenses can't, so it definitely has its uses, provided you can get it to focus accurately. Edward has not yet said which of the supported lenses do/don't suffer from the focus shift issue, but based on user reports the Nikon F 105mm is the main one that is currently known to perform very well.
×
×
  • Create New...