Opteka 6.5mm circular fisheye lens - more field testing

After using a Fujifilm X-T5 camera and an Opteka 6.5mm circular fisheye lens from Amazon to shoot Scenes 1-3 with the lens pointed straight up at the zenith, the camera/lens rig was relocated to the edge of the parking garage for a fisheye view of both the sky above and Richmond Highway below. Two more photo sets were captured.

Scene 4

The following photo is the first image in a time series of 344 images. The JPG photo is shown "as is," that is straight out of the camera without post-processing. As you can see the sky is overexposed, especially noticeable in the clouds.

6.5mm APS-C | f/8?+ | 1/250 s | ISO 200 | 7728 x 5152 pixels

The next photo is a post-processed .raf file -- Fujifilm's proprietary RAW image format -- exported as a JPG. Notice I was able to recover some of the detail in the clouds that was lost in the overexposed photo. So what are the takeaways? First, try to get the exposure right in-camera. Failing that, sometimes it's worth the time and effort to post-process the RAW files before rendering time lapse video.

6.5mm APS-C | f/8?+ | 1/250 s | ISO 200 | 7728 x 5152 pixels

As a sidebar let's briefly discuss exposure for all sky photography.

The Opteka 6.5mm circular fisheye lens doesn't feature filter threads because the front lens element is so bulbous you can't use filters with the lens (e.g., circular polarizing filter, neutral density filter, etc.). So how can you set exposure to avoid blown highlights?

Remember the exposure triangle? Lower ISO equals less light sensitivity; smaller aperture (higher f/number) means less light enters the lens; and faster shutter speed means less light enters the lens.

I'm already using a low ISO. I don't want to reduce the aperture since f/8 seems to be widely regarded as the "sweet spot" for this lens. So I recommend turning on "blinkies" and increasing the shutter speed until the blinkies disappear. Blown highlights cannot be recovered. On the other hand, it's usually possible to recover detail from shadows.

The following ProRes video was created using Apple "QuickTime Player." This video was made using the "as is" JPG photos with blown highlights.

25 August 2026 | 2:07 PM - 2:13 PM EDT | Fairfax County, Virginia USA

344 photos at 1 s interval

Notice the interval between photos was set for 1 second in order to capture the vehicle traffic along Richmond Highway (U.S. Route 1). The Fujifilm X-T5 was able to save FINE+RAW files to a memory card without a problem.

The next video was created using Apple "QuickTime Player" and edited using Apple "Photos."

25 August 2026 | 2:07 PM - 2:13 PM EDT | Fairfax County, Virginia USA

344 photos at 1 s interval

Scene 5

The following photo is the first image in a time series of 59 images. The JPG photo is shown "as is," that is straight out of the camera without post-processing. As you can see, the sky is exposed properly, preserving detail in the clouds.

6.5mm APS-C | f/8?+ | 1/1,000 s | ISO 200 | 7728 x 5152 pixels

I started recording another time lapse.

25 August 2026 | 2:14 PM - 2:15 PM EDT | Fairfax County, Virginia USA

59 photos at 1 s interval

The memory card was full soon after the time lapse began. I knew there was only one memory card in my Fujifilm X-T5, but I was in a rush to get to the roof so I took a chance that one card would be sufficient. I didn't realize the 64 GB memory card would fill so quickly due to the HUGE file size of photos captured by the X-T5 using the following settings: IMAGE SIZE = L 3:2 7728 x 5152 40 M; IMAGE QUALITY = FINE+RAW; RAW RECORDING = LOSSLESS COMPRESSED.

I'm planning to test using an IMAGE SIZE of M 3:2 5472 x 3648 (20M). That's comparable to an IMAGE SIZE of L 3:2 6240 x 4160 (26M) using my Fujifilm X-T3.

Tech Tips

The Opteka User Manual includes the following information in the section entitled "Focusing Aides."

Many compatible cameras provide aides for manual focus precision. The two most common aides are Focus Peaking, and/or a Focus Magnifier. Be sure to consult your camera's user manual for assistance with configuring these features. Source Credit: Opteka 6.5mm f/2.0 HD Multi-Coated Lens User Manual, p. 6.

In my experience "focus peaking" and "focus magnifier (Focus Check)" are easier to use under controlled conditions such as a photo studio. My next blog post will feature a discussion of some "hacks" for focusing that I use when shooting in the field.

Related Resources

• Opteka 6.5mm circular fisheye lens - first field test - a blog post by Walter Sanford
• What's wrong with this picture? - another blog post by Walter Sanford
• Posts on Walter Sanford's Blog with the label "all sky."
• Fujifilm X-T5 Owner's Manual

Copyright © 2026 by Walter Sanford. All rights reserved. 

Opteka 6.5mm circular fisheye lens - first field test

I bought an Opteka 6.5mm circular fisheye lens from Amazon recently. Given the similarities in its physical appearance and specifications, it's possible/probable the Opteka lens is a rebranded version of the Meike 6.5mm circular fisheye lens. Does the Opteka lens perform as well as the Meike? This post is the beginning of my answer to that question.

Three photo sets were captured using a Fujifilm X-T5 and the Opteka lens. Each photo set was rendered to video using Apple "QuickTime Player." I decided to share the resulting all sky time lapse videos "as is," meaning unedited, so you can see exactly what the camera/lens combo "saw" and judge for yourself how well the Opteka lens works.

Scene 1

The camera was mounted on a tripod with the lens facing the zenith. The entire dome of the sky is shown in the circular field of view; the horizon is located around the outer rim of the circle.

6.5mm APS-C | f/8?+ | 1/3,200 s | ISO 200 | 7728 x 5152 pixels

The aperture was "f/8?+" meaning it's unclear whether the f/8 mark on the focus ring is actually f/8, plus the ring was set slightly beyond the f/8 mark.

"No click stops on the aperture ring, so you have to keep checking to see if you've moved it. Also, marked apertures are not accurate. You need to turn beyond the marking to get the marked aperture." Source Credit: "Amazing Bargain, but Not Easy to Use," by Killersax (product review on Amazon Web page).

The next photo shows (better than words can describe) how the lens was actually set for all three scenes.

The following ProRes video was created using Apple "QuickTime Player."

25 August 2026 | 1:29 PM - 1:39 PM EDT | Fairfax County, Virginia USA

298 photos at 2 s interval

Scene 2

6.5mm APS-C | f/8?+ | 1/3,200 s | ISO 200 | 7728 x 5152 pixels

The following ProRes video was created using Apple "QuickTime Player."

25 August 2026 | 1:40 PM - 1:51 PM EDT | Fairfax County, Virginia USA

313 photos at 2 s interval

Scene 3

6.5mm APS-C | f/8?+ | 1/3,200 s | ISO 200 | 7728 x 5152 pixels

The following ProRes video was created using Apple "QuickTime Player."

25 August 2026 | 1:52 PM - 2:02 PM EDT | Fairfax County, Virginia USA

313 photos at 2 s interval

Tech Tips

The dimensions of the JPG photos used to create all three time lapse videos are 7728 x 5152 pixels. That's way more than the resolution of Ultra High Definition, a.k.a., UHD (3840 x 2160 pixels)!

"YouTube officially supports maximum playback and upload resolutions up to 8K (4320p or 7680 × 4320 pixels)." Source Credit: Google AI Overview.

Click on the "Settings" button (gear icon) in the YouTube player and select the highest "Quality" available on your device.

Related Resources

• Opteka 6.5mm circular fisheye lens - more field testing - a blog post by Walter Sanford
• What's wrong with this picture? - another blog post by Walter Sanford
• Posts on Walter Sanford's Blog with the label "all sky."

Copyright © 2026 by Walter Sanford. All rights reserved.

What's wrong with this picture?

I bought an Opteka 6.5mm circular fisheye lens from Amazon recently. The following image is one of the actual product photos featured on Amazon.

Opteka 6.5mm circular fisheye lens product photo on Amazon.

The next image is a photo of the lens that I received from Opteka/Circuit City/Amazon.

Opteka 6.5mm circular fisheye lens mounted on Fujifilm X-T5.

Hmm, what's wrong with this picture? (Remember that type of children's puzzle?) Look closely at the focus ring in both images. The lenses shown in the two images are similar but not identical, and the difference is critical. Unlike the product photos on Amazon there aren't any distance numbers (ft and m) marked on the focus ring of the Opteka lens that was delivered to me.

Instead of distance numbers the focus ring is marked "←Near" "Far→" and "∞" (infinity). The "←Near" label on the focus ring turns far to the left of the index mark on the lens barrel, presumably beginning at the closest focusing distance of the lens; the "∞" label also turns far to the left of the index mark. That's right, the Opteka lens focuses "to infinity and beyond." Way beyond.

Opteka, Circuit City, and Amazon are guilty of false advertising.

"False advertising is any published claim or statement used to promote a product or service that is untruthful, deceptive, or misleading to a reasonable consumer." Source Credit: Google AI Overview.

In my strong opinion Opteka, Circuit City, and Amazon should carefully consider offering some form of restitution other than simply returning the lens for a full refund. I'm open to suggestion.

The Backstory

I bought the Opteka 6.5mm circular fisheye lens because it's available for Fujifilm X Mount camera bodies while the comparable Meike version is no longer available.

"Opteka frequently rebrands and sells lenses produced by other Chinese and Korean manufacturers, including Meike and Samyang (Rokinon)." Source Credit: Google AI Overview.

Does the Opteka lens perform as well as the Meike? I don't know, yet.

I would like to be able to recommend the Opteka lens as a viable option to replace the Meike lens. First I need to do some field testing to see how the Opteka lens performs. (Limited studio testing is inconclusive so far.)

For now my recommendation is "buyer beware -- what you see is not what you get!" You might call the product photos on Amazon an "Optekal Illusion," but seriously, false advertising is an egregious matter.

Related Resources

• Opteka 6.5mm circular fisheye lens - first field test - a blog post by Walter Sanford
• Posts on Walter Sanford's Blog with the label "all sky."

Post update: Both the Web site address (http://www.Opteka.com) and e-mail address (support@opteka.com) listed in the hardcopy User Manual (included in the box with the lens) are invalid. #shellcompany?

Copyright © 2026 by Walter Sanford. All rights reserved.

Oh beautiful ...

Oh beautiful, for spacious skies. Source Credit: America the Beautiful.

This blog post is an homage to Jack Borden, founder of "For Spacious Skies," a non-profit organization "committed to promoting the beauty of the sky as a visual feast that anyone, anywhere, and at any time could partake." Source Credit: BORDEN, Jacob “Jack” - Local Newscaster & Founder of For Spacious Skies.

Sometimes the sky is astoundingly beautiful. Friday, 31 July 2026 was one of those days. Click on the following panoramic composite image to see the full-size version.

31 JUL 2026. 2:40 PM. Panoramic view. (15274 x 3806 pixels.)

I decided to share two "as is" all sky time lapse videos, meaning unedited, so you can see exactly what the camera/lens combo "saw."

31 July 2026 | 1:34 PM - 1:54 PM EDT | Fairfax County, Virginia USA

6.5mm APS-C | f/8 | 1/4,000 s | ISO 160 | 623 photos at 2 s interval

Beautifully saturated blues and almost no blown highlights is the result of using faster shutter speeds, enabling me to capture the dynamic nature of the low level cumuliform clouds (moving generally from north-to-south across the sky).

Notice the sunstar (a.k.a., sunburst) that is visible in the second video during breaks in the clouds. A distributor of the lens says the sunstars are 18-point, although I haven't counted the points to verify that claim. (See the Post update at the bottom of this page.)

"A sunstar forms when brilliant, direct sunlight (or any other bright light) diffracts (spreads) as it passes through the overlapping blades of a lens iris (its aperture). These are the blades that open to admit more light (small f-number), and close to limit light (large f-number)." Source Credit: Sunstars, by Gary Hart.

31 July 2026 | 2:01 PM - 2:23 PM EDT | Fairfax County, Virginia USA

6.5mm APS-C | f/8-ish | 1/6,400 s | ISO 160 | 636 photos at 2 s interval

The aperture was "f/8-ish" for the photos used to create the second time lapse, meaning the clickless aperture ring was set a little higher than f/8. What was the actual f/stop? I don't know because the aperture ring for the Meike 6.5mm circular fisheye lens doesn't have any markings between f/8 and f/22, plus the lens is manual only (with no electronic contacts) so there isn't any communication between the lens and camera body.

Tech Tips

The dimensions of the JPG photos used to create both time lapse videos are 6240 x 4160 pixels. That's way more than the resolution of Ultra High Definition, a.k.a., UHD (3840 x 2160 pixels)!

"YouTube officially supports maximum playback and upload resolutions up to 8K (4320p or 7680 × 4320 pixels)." Source Credit: Google AI Overview.

Click on the "Settings" button (gear icon) in the YouTube player and select the highest "Quality" available on your device.

Related Resources

• For Spacious Skies - Jack Borden (14:15) - a YouTube video by Sam Ruocco [The video becomes repetitive toward the end but the first two-thirds is worth watching.]
• "Skyku©" poetry - a blog post by Walter Sanford
• Posts on Walter Sanford's Blog with the label "all sky"

Post update: Yep, that's an 18-point sunstar!

Copyright © 2026 by Walter Sanford. All rights reserved.

X-T3 Sky Lapse

The following YouTube video includes two time lapse video clips that show the sky over Fairfax County, Virginia USA during the afternoon on 27 July 2026. Two photo sets were captured using a Fujifilm X-T3 and the 18-55mm kit lens. Each photo set was rendered to video using Apple "QuickTime Player"; each movie clip was edited using Apple "Photos." The final video was created using DaVinci Resolve.

27 July 2026 | Fairfax County, Virginia USA

Low level cumuliform clouds were moving generally from north-to-south.

Panoramic Image

The following panoramic composite image was taken using the "Camera" app on my Apple iPad mini 6, set for "Pano" mode. The iPad was mounted on a tripod located in the shade of the tree shown at the right side of the image.

27 JUL 2026. 3:28 PM. Panoramic view. (16350 x 3870 pixels.)

Have I mentioned how much I love the look and feel of the panoramic composite images created using the Apple "Camera" app? I love it so much I would marry it. Easy to use. Excellent output. Good job by you, Apple!

Wind (mph), Weather and Sky Condition

"Wind (mph)," "Weather" and "Sky Cond." are highlighted by red rectangles in the following excerpt from a table of three-day weather observations for KDCA on 27 July 2026 nearest the times when I recorded the photos used to create the time lapse video, and the panoramic composite image.

Source Credit: KDCA | National Weather Service.

Tech Tips

My Fujifilm X-T3 camera was set for manual exposure and manual focus. Aperture was set for f/8. Shutter Speed was 1/500 second. ISO was set for 160. White Balance was set for "Daylight." The focal length of the 18-55mm kit lens was set for 18mm (27mm, 35mm equivalent). Aspect Ratio was set for 16:9 (6240 x 3512 pixels). Image Quality was set for FINE+RAW (Fine JPEG plus RAF).

The ELECTRONIC LEVEL was turned on. The manual focus DEPTH-OF-FIELD SCALE was set for "FILM FORMAT BASIS."

I selected a two (2) second interval between photos. Scene 1 = 602 photos. Scene 2 = 612 photos. Both photo sets lasted approximately 20 minutes in real time.

Related Resources: Posts on Walter Sanford's blog with the label "Fujifilm X-T3."

Copyright © 2026 by Walter Sanford. All rights reserved.

Another GoPro Panoramic Sky Lapse

The following panoramic time lapse video shows the sky above Fairfax County, Virginia USA on 21 July 2026 beginning at 1:06 PM EDT. The video was recorded using my GoPro HERO4 Black action camera mounted on an inexpensive mechanical one-hour kitchen timer.

21 July 2026 | Fairfax County, Virginia USA

The GoPro video was recorded after the "22 degree halo" all sky time lapse video featured in my last blog post. Regrettably the halo isn't visible in the GoPro video.

Panoramic Image

The following panoramic composite image was taken using the "Camera" app on my Apple iPad mini 6, set for "Pano" mode.

21 JUL 2026. 1:38 PM. Panoramic view. (14487 x 3785 pixels.)

RadarScope

Low level cumilform clouds (shown in the preceding panoramic composite image) were growing larger and darker ahead of an area of thunderstorms advancing from west to east.

RadarScope (app) animation | 1:39 PM to 1:58 PM EDT.

Tech Tips

The camera was set for "Video" mode / "Time Lapse Video" submode at a resolution of 4K and an interval of two (2) seconds.

I don't set the kitchen timer for a specific amount of time -- I just turn the dial clockwise until it's set for one hour. Then I compose the shot (by rotating the ball head to check the end points of the panoramic view) and start recording for as long as I need/want.

"CommerciaLapse," one of my earlier blog posts, features photos and a detailed description of the magnet-free rig I use for mounting the one-hour mechanical kitchen timer on a tripod plus a description of how the GoPro is mounted on the timer.

Related Resources

• 22 degree halo - a blog post by Walter Sanford
• RadarScope app - available for both Apple iOS and Android operating systems
• Search results for "RadarScope app" tag from walter sanford's photoblog (4 posts)
• Posts on Walter Sanford's blog with the labels "GoPro" and/or "one-hour kitchen timer"

Copyright © 2026 by Walter Sanford. All rights reserved.

22 degree halo

A time series of 412 photos was taken during the afternoon on 21 July 2026 using my Fujifilm X-T1 camera and a Meike 6.5mm circular fisheye lens. The first photo was shot at 12:37 PM; the last photo at 12:58 PM.

The camera was mounted on a tripod with the lens facing the zenith. The entire dome of the sky is shown in the circular field of view; the horizon is located around the outer rim of the circle.

21 July 2026 | Fairfax County, Virginia USA

A 22° halo around the Sun is visible high in the sky.

The small halo appears as a white or mostly white luminous ring of 22° radius with the light source (Sun or Moon) at its centre. ... The sky inside the ring is conspicuously darker than the rest of the sky. The halo always has a 22° radius regardless of its position in the sky. Source Credit: 22° halo, International Cloud Atlas, World Meteorological Organization.

Camera Settings

The camera was set for manual exposure and manual focus. The Meike lens features a "clickless" aperture ring. The Aperture was set for the f/8 mark on the aperture ring. The manual focus ring was set near the 3 ft mark. The Shutter Speed was set for 1/4,000 s, the fastest mechanical shutter speed featured on the Fujifilm X-T1. 

The camera was set to record FINE+RAW, in L 3:2 format (4896 x 3264 pixels). The film simulation was set for Provia/Standard. A three (3) second interval was used to allow sufficient time for the camera to save the photo files to a memory card.

Panoramic Image

The following panoramic composite image was taken using the "Camera" app on my Apple iPad mini 6, set for "Pano" mode. The iPad was mounted on a tripod located at my usual vantage point on top of a seven-story parking garage.

21 JUl 2026. 1:28 PM. Panoramic view. (14402 x 3877 pixels.)

Notice the low- and middle level cumuliform clouds.

Wind (mph), Weather and Sky Condition

"Wind (mph)," "Weather" and "Sky Cond." are highlighted by red rectangles in the following excerpt from a table of three-day weather observations for KDCA on 21 July 2026, nearest the times when I recorded the time lapse videos and panoramic composite photo.

Source Credit: KDCA | National Weather Service

The preceding table shows the surface wind direction is from the south-southwest. High level cirrostratus clouds (Cs) were streaming across the sky from west to east, as shown in the time lapse video. The difference in wind direction indicates vertical wind shear.

Tech Tips

The camera-lens combo was mounted on a ball head/tripod so that the lens is pointed at the zenith. Notice the green plastic spirit level mounted on the X-T1 hot shoe, used to level the camera body in this orientation.

Camera-lens combo mounted on ball head/tripod.

Apple "QuickTime Player" was used to render 412 JPEG images from the photo set into a time lapse video. The video was edited lightly using Apple "Photos." The post-processed video clip was made into a YouTube movie using "DaVinci Resolve."

Related Resources

• Halo Phenomena | International Cloud Atlas - World Meteorological Organization
• 22° halo | International Cloud Atlas - World Meteorological Organization
• Ice Crystal Halos - one of many good resources available from the Atmospheric Optics Web site
• 22 Degree Halo - WW2010 | Department of Atmospheric Sciences (DAS) at the University of Illinois at Urbana-Champaign
• Rainbows, Halos and Glories, by Robert Greenler [excellent reference book]
• Results for the query "halo" on Walter Sanford's Blog

Copyright © 2026 by Walter Sanford. All rights reserved.