Search found 439 matches

by cactuspic
Wed Dec 06, 2023 9:25 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: "Halo'ing" when focus stacking many images
Replies: 8
Views: 3626

Re: "Halo'ing" when focus stacking many images

It looks like a "highlight bloom" in Pmax. Take a look at the highlight exposure of your slices and see if they have highlights that are at pure white or close to pure white on the histogram. If so, see if you can get about one stops worth of headroom. In Lightrooom it is easy to do so for the set o...
by cactuspic
Sun Jan 02, 2022 7:03 am
Forum: Equipment Discussions
Topic: Photons to Photos Optical Bench and Focus Breathing
Replies: 23
Views: 2656

Re: Photons to Photos Optical Bench and Focus Breathing

Thanks for the reference, Robert. I suspect that one of the reasons for the dramatic change in focal length between the EF and RF versions of the 100mm macro lenses by Canon has to do with the change in the maximum magnification of the two lenses. The maximum magnification of the EF version is 1x. T...
by cactuspic
Wed Jul 29, 2020 7:39 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Would you recommend a tripod or monopod for macro in the field?
Replies: 23
Views: 9394

Re: Would you recommend a tripod or monopod for macro in the field?

I use a tripod with a boom arm. Though not quite as stable as a simple tripod, I find it more stable than hand holding or a monopod and it provides a stable enough platform to stack. I tend to shot botanicals so I am not worried about chasing a moving insect. Also, most of my higher magnification wo...
by cactuspic
Sun Dec 01, 2019 6:12 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Zerene control of Stackshot with studio white box and flash
Replies: 4
Views: 2469

Rik, i had a question as to why flash would be sharper. Is it the difficulty in isolating the system from vibration? Or is there another reason. I assume that the benefit is flash's short duration that prevents any movement. If we didn't try so hard to diffuse it, I could see an additional benefit f...
by cactuspic
Sun Dec 01, 2019 5:53 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: This is a different use for stacking software
Replies: 2
Views: 2382

Fun creative shot Mark.

Irwin
by cactuspic
Fri Sep 28, 2018 9:03 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: A better camera calibration profile for stacking (RAWs)
Replies: 8
Views: 3431

I am a bit confused. I presently shoot with a camera profile based upon my camera, lighting, and lens derived by using a Passport Color Checker. I noticed that the Passport has several gray as well as white and black pigment chips. Is the resultant color profile linear? If not is is possible to comb...
by cactuspic
Thu Feb 22, 2018 8:06 am
Forum: Equipment Discussions
Topic: Longitudinal Chromatic Aberration 1X Macro Lens Test
Replies: 42
Views: 9926

Thank you Robert. I always appreciate the care and precision that you apply to your testing. I also have a bit of a cautionary tale, because I did not use the test information correctly at first. In particular, I love the sharpness and overall quality of the images produced with my Sigma 180 mm 2.8....
by cactuspic
Wed Dec 20, 2017 5:56 pm
Forum: Equipment Discussions
Topic: 4X Objective Lens Test Comparison - Part 1
Replies: 31
Views: 6842

Robert, thanks for all your care and effort. The tests really help those of us on a limited budget more efficiently buy equipment that makes a difference in our photography. Great work.

Irwin
by cactuspic
Sun Jul 03, 2016 8:06 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Shooting at lesser magnification to increase DOF?
Replies: 6
Views: 2044

Agreed Chris. It's a decision I have made with the diffraction devil :evil: many times...gladly. :)
by cactuspic
Sun Jul 03, 2016 4:59 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Shooting at lesser magnification to increase DOF?
Replies: 6
Views: 2044

Thanks Chris. I do play with a homemade tilting macro lens, a reversed 90mm APO Componon, but it is not the quickest or most elegant to adjust when photographing lively critters.
by cactuspic
Sun Jul 03, 2016 11:44 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Shooting at lesser magnification to increase DOF?
Replies: 6
Views: 2044

Thanks, Pau. In applying the no free lunch rule, I was wondering where the payment would come from.
by cactuspic
Sun Jul 03, 2016 9:45 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Shooting at lesser magnification to increase DOF?
Replies: 6
Views: 2044

Shooting at lesser magnification to increase DOF?

Recently, I was corresponding with another macro shooter who stated: "...but the inherent narrow DoF, even at f/16, quite often leaves some of the subject outside of acceptable focus. Quite often, we will photograph a subject at less than 1:1 mag, but deeper DoF. We then crop to the same size as if ...
by cactuspic
Mon Feb 22, 2016 10:54 am
Forum: Equipment Discussions
Topic: Tilting macro lens
Replies: 5
Views: 1634

wouldn't it be better to tilt as near as possible to the camera in order to avoid vignetting, similar Zoerk does: http://www.zoerk.com/pages/p_mfs.htm Given that the lens was reversed and that there was significant extension, the image circle should be huge. In my limited understanding of optics, I...
by cactuspic
Sun Feb 21, 2016 10:13 pm
Forum: Equipment Discussions
Topic: Tilting macro lens
Replies: 5
Views: 1634

Chris, In what may be a "snatch defeat from the jaws of victory" moment, the vignetting was added post capture in Lightroom. :) I've not noticed any vignetting problems with the Kenko tubes nor have i noticed any difference when I use the non-automatic tubes. I have attached a version without the vi...
by cactuspic
Sun Feb 21, 2016 4:12 pm
Forum: Equipment Discussions
Topic: Tilting macro lens
Replies: 5
Views: 1634

Tilting macro lens

A while ago, I saw an APO 90mm Componon that no one else bid on in an Ebay auction. I bought the lens for approximately $100. I then decided to build a tilting macro lens. I reversed the lens, used parts from an old bellows, some scrapwood and about $15 of hardware. After I built it, but before I co...