Search found 27 matches

by Kevin Childress
Mon May 08, 2017 12:36 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Perplexed with an extension tube
Replies: 7
Views: 1686

Closing the loop (for now at least) ... I spoke to Savage about the tube keeping the aperture stopped down all the time. They commented on having seen a few issues where the tube wouldn't "click" into place on the lens but they didn't seem to want to discuss reports of an overly tight fit to the len...
by Kevin Childress
Mon May 01, 2017 2:28 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Vignetting with Reversed 50
Replies: 9
Views: 1376

NikonUser wrote:117 mm exension tubes behind the Nikon 105 gives >2:1 magn. with min. vignetting
NikonUser, right on. I've been testing recently with 71mm of extension and that's getting me 1.9x and my vignetting looks practically just like on your grid paper.
by Kevin Childress
Mon May 01, 2017 2:21 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Vignetting with Reversed 50
Replies: 9
Views: 1376

Re: Vignetting with Reversed 50

Unfortunately it sounds like that particular model of lens has its entrance pupil far backward. Indeed, the diaphragm is set back a ways from the front of the lens. As Enrico says, the best bet is usually to have the rear lens wide open and focused at infinity. That usually pushes the entrance pupi...
by Kevin Childress
Mon May 01, 2017 2:18 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Vignetting with Reversed 50
Replies: 9
Views: 1376

This 105mm lens seems to be a bit of a problem child with vignetting - I've had someone ask about it on my site too in the past and I've seen the vignetting on other shots using that lens. I've seen it be more successful though with both lenses wide open, maybe give that a try. Thanks for the reply...
by Kevin Childress
Mon May 01, 2017 2:14 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Vignetting with Reversed 50
Replies: 9
Views: 1376

Enrico, Thanks for all the input. A few ideas below ... The general suggestion is stopping down the front (reversed 50 mm) lens and leaving the rear (105 mm, normally mounted and usually focused at infinity) lens fully open. From your description it sounds like you are doing the opposite. If you sto...
by Kevin Childress
Mon May 01, 2017 7:19 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Vignetting with Reversed 50
Replies: 9
Views: 1376

Vignetting with Reversed 50

I wanted to share an experience I've had using a reversed Nikon 50mm f/1.8 mounted to a Nikon 105mm f/2.8 micro. I've always thought that using a reversed 50 was one of the more common alternatives to increasing reproduction ratio but I've never heard this issue mentioned using a setup like this. I'...
by Kevin Childress
Sun Apr 30, 2017 1:48 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Perplexed with an extension tube
Replies: 7
Views: 1686

Rik, Pau, and Chris, Thanks to you all for the help. I felt like an idiot as soon as I read the first replies here. I should have realized the problem when I shot those other f/stops and didn't compensate for exposure. So yeah, the aperture is staying stopped down - all the way down - all the time. ...
by Kevin Childress
Sat Apr 29, 2017 3:00 pm
Forum: Macro and Micro Technique and Technical Discussions
Topic: Perplexed with an extension tube
Replies: 7
Views: 1686

Rik, I'm not sure what you mean about checking the exposure time. I mean, I know all the images shot with the extension tube were at 1/250th, but not sure what else there is to know about it. Your idea about the lens being stopped down all the way, all the time, is as good of an explanation as I can...
by Kevin Childress
Sat Apr 29, 2017 11:55 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Perplexed with an extension tube
Replies: 7
Views: 1686

Perplexed with an extension tube

Looking for help to understand a problem with image quality. I'm shooting a D810 with Nikkor 105mm f/2.8 micro. The extension tube is a variable tube (55 - 71mm) from Savage and seems like a very well built piece of equipment. I used the tube at 55mm and noticed right away the extension tube dramati...
by Kevin Childress
Wed Apr 27, 2016 8:44 am
Forum: Equipment Discussions
Topic: Design Help With My Macro Table
Replies: 0
Views: 214

Design Help With My Macro Table

At the heart of my macro photography is my "macro table" - a piece of equipment originally designed for photographing 35mm film slides. I adapted this table to my macro setup because of the precise control it offers for X and Y axis adjustments (see the two adjusting screws on the rear and right sid...
by Kevin Childress
Wed Apr 27, 2016 8:41 am
Forum: Equipment Discussions
Topic: Need Design Help With My Macro Table
Replies: 0
Views: 198

Need Design Help With My Macro Table

At the heart of my macro photography is my "macro table" - a piece of equipment originally designed for photographing 35mm film slides. I adapted this table to my macro setup because of the precise control it offers for X and Y axis adjustments (see the two adjusting screws on the rear and right sid...
by Kevin Childress
Fri Aug 28, 2015 8:25 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Bokeh Backgrounds for Macro Images?
Replies: 3
Views: 1326

Yesterday I posted a question discussing how one might create a bokeh effect with macro backgrounds. Clearly I already had an idea of how I wanted to attempt that by punching holes in background paper and back-lighting the holes, so I refined the approach a bit and here's what I got. I mostly got wh...
by Kevin Childress
Thu Aug 27, 2015 2:33 am
Forum: Macro and Micro Technique and Technical Discussions
Topic: Bokeh Backgrounds for Macro Images?
Replies: 3
Views: 1326

Bokeh Backgrounds for Macro Images?

Despite that I am primarily discussing bokeh here, I would appreciate any tips you have for creating more interesting backgrounds for macro images. For me creating interesting backgrounds for macro is definitely the most difficult aspect of the entire process. As such my backgrounds are typically bl...
by Kevin Childress
Sun Aug 23, 2015 4:00 am
Forum: Equipment Discussions
Topic: Reversed Lens Aperture Control
Replies: 9
Views: 1627

I completed my first round of tests with this aperture controller and I may have to forego the idea of marking the adapter with literal/accurate f/stops. The mathematical approach is just beyond me so I won't be marking the adapter with any numbers at all. In my testing I was using marked tape just ...
by Kevin Childress
Fri Aug 21, 2015 7:14 am
Forum: Equipment Discussions
Topic: Reversed Lens Aperture Control
Replies: 9
Views: 1627

ChrisR wrote:Or a step-up ring, then you could fix a pointer to it!
Yep, I'm actually looking at a step-up ring right now!