Macro Filters vs Extension Tubes

[480sparky]

What about focus stacking with what you have? This is something I plan to try but I suspect it is a lot of work and takes a lot of practice.

I don't understand how focus-stacking will help with taking a picture of a flat slide.

Field curvature of the lens may cause parts of the image to be OOF. Stopping down may solve that problem, but introduce diffraction.

 

[TWX]

What about focus stacking with what you have? This is something I plan to try but I suspect it is a lot of work and takes a lot of practice.

I don't understand how focus-stacking will help with taking a picture of a flat slide.

Field curvature of the lens may cause parts of the image to be OOF. Stopping down may solve that problem, but introduce diffraction.

gotchya.

We'll see. Right now I'm dealing with multiple pictures due to lighting already, so adding multiple focus distances might be more post-processing work than I care for.

 

[photoflyer]

I don't understand how focus-stacking will help with taking a picture of a flat slide

It sounded like we shared a challenge with our existing gear: shallow depth of field even at very small aperture settings. I was experimenting today with a 400mm lens that enables me to focus at about 1 foot and the DOF at f 14 was still just a few millimeters.

 

[Original katomi]

These were taken using canon 70D canon 17 85 @f11 whilst tethered to lap top using a 35mm ex tube
It could be better but I would have to learn and use image stacking
I have found out that my ring light can’t be used with l glass the filter size is way to big for

 

[TWX]

View attachment 185463
These were taken using canon 70D canon 17 85 @f11 whilst tethered to lap top using a 35mm ex tube
It could be better but I would have to learn and use image stacking
I have found out that my ring light can’t be used with l glass the filter size is way to big for

Mineral deposit? It shares some resemblance to a copper foundry slag drop that I have but just a little too different.

 

[Original katomi]

It’s a glass paper weight glass within glass

 

[petrochemist]

Filters = glass. Extra glass = increased image degradation.

If that's true, why do lens designers use such complex designs, more than 10 elements is now quite common, yet the earliest cameras used single element lenses..........

Because they're forced to design lenses with a fixed flange-to-focal plane distance.

You can generally manage to design a lens of the desired focal length & flange distance with two elements.
They don't do this because of the numerous aberations that are not corrected with such a simple design.
Even in simple close up filters adding a second element for an achromatic doublet makes a huge improvement in image quality.

 

[petrochemist]

Quite a bit of food for thought here.

There's a local craigslist seller with some various macro filters for sale cheap, I might start there depending on what strengths and sizes he has.

If they are being sold cheap then they will be single element ones which will give poorer results. They might give good enough results but it's more likely they just make you think diopters are a waste of time.

A 50mm prime (even a legacy one if you don't have one now) & a suitable coupling ring to fit it reversed to the front of a short telephoto or normal lens will generally give excellent results. The reversed prime being a highly corrected 'close up filter' Even just holding the lens in place can give you an idea of how well it works. The technique is better described here & the rest of Johan's site will give a good idea of what other techniques can manage too... (He manages MUCH better than I can)

 

[TWX]

So to return to focus stacking, I did a little light reading and I was surprised by a lack of in-camera implementation by Canon, Nikon and Sony, while having been implemented in-camera for quite some time in various Olympus and Panasonic cameras, including even some pocket cameras.

I wonder if at least in Canon's and Nikon's cases, if legacy lenses are subject to enough focus breathing as to make many popular lenses unsuitable to focus stacking, and since both have thought in terms of DSLRs more than mirrorless, simply aren't accustomed to the in-camera programming.

The new Canon EOS RP apparently does have the feature though, so perhaps they're waking up to a desire for it.

 

[Overread]

Focus stacking is a VERY hit and miss affair. I've had stacks that will fail with one program and work with another. Even each program often has several different modes of working to stack slightly differently.

It's a little like a lot of "in camera editing" in that "yes it can work but once you're past snapshots it might fail."

Zerene Stacker; Helicon Focus; Combine ZP (legally free); Photoshop - all those and several more all do stacking and each does it slightly differently in how they work with the photos.
In general having it out of the camera and working with the original photos is much easier since you're working with the full data block and can manipulate it. You can pull out a frame that's causing problems or take two or three sets and swap frames over to make it work.

"Breathing" won't be a huge issue because with any stacking you'll get some breathing going on. The edges are always a "waste" area so you have to learn to frame wide so that when you take the last shot you've got the whole of the subject in the frame with some space around the edge. If you start with the furthest shot like that then no matter if you're focusing closer; zooming or moving the lens/subject closer etc... you'll get bits chopped off.



For a film slide though I'd likely just set things to a very small aperture (f13) and then shine light through the back of the film (at an angle and with diffusion). Film slides/negatives are see-through so you don't need the light coming from in front, it can be coming from behind.

 

[Derrel]

Not sure how we got to focus stacking as it somehow might be useful when copying slides... if you are doing it right there is absolutely no reason at all that you would need more than one Focus point. Focus correctly and you've got it. One shot is all that is needed.

 

[webestang64]

Back in the film days I used a Nikon (F2) 55mm 1:2 macro lens with an extension tube (made the lens 1:1) for slide dupes or "inter-negs" (special C-41 film for negs from slides). My light source was a homemade light table with daylight bulbs. Worked great!!

 

[TWX]

So I went ahead and ordered a $15.99 set of autofocus extension tubes off Amazon. My guess is that they won't stack together quite as well as more expensive products, but for my purposes I'm sure they'll be fine. Metal mounts with ABS plastic barrel sections supposedly.

 

[SquarePeg]

So I went ahead and ordered a $15.99 set of autofocus extension tubes off Amazon. My guess is that they won't stack together quite as well as more expensive products, but for my purposes I'm sure they'll be fine. Metal mounts with ABS plastic barrel sections supposedly.

I’ve never found auto focus to work with the tubes. You want MF anyway so you can use focus peaking.

 

[TWX]

77D doesn't have focus peaking in the turn-focus-area-red sort of thing. Besides, the focus ring might be inaccessible depending on lens choice and final design of the assembly, autofocus might be necessary.