www.dxomark.com does scientific testing of lenses mounted on various camera bodies.
The last time I checked, they have tested 11,209 combinations.
Interestingly, the top zoom lens comes in at #262 on the list with a score of 35.
That means the top 261 lenses are all prime lenses with the #1 lens being a Sigma 85 mm with a score of 51.

Once you get a sturdy tripod and tripod head, you may also wish to use a "focusing rail" for macro work.
The rail attaches to the tripod head; your camera attaches to the rail. You can then fine tune the camera's placement.
The best type will not only allow you to go forward and back but also right or left.

Yes, yes, I'm aware that a 120 mm is a 120 mm.
In this case, the 120 mm is producing a medium format sized image circle.
Rather than "using" all of that image circle by using a medium format camera to "catch" it,
I'm using an APS-C sensor to crop a tiny portion out of the large image circle.
Call it whatever you want, it works well to photograph butterflies.

Imagemeister said:
"The crop factor for D7100 is 1.5X - just so we all know ....NOT 2.5X ! So, you end up with 180mm FF Equiv. "

Imagemeister,
You did not clearly read my post.
I am not using a 35mm (Full Frame) (36 mm x 24 mm) size 120 mm lens for which the crop factor would indeed be 1.5 x.
I am using a MEDIUM FORMAT lens from a MEDIUM FORMAT Pentax 645 camera (60 mm x 45 mm).
For that, the crop factor is indeed 2.5 x.
Hence the "equivalent" becomes 120 mm x 2.5 equals 300 mm.
I also use a "full frame" 90 mm macro lens for which the crop factor is 1.5x.
The 90 mm becomes the "equivalent" of a 135 mm lens.

I was at Butterfly World in Florida about two months ago. I think this was my third visit there.
They don't allow tripods or monopods. I ended up using (for all of my shots) a 120 mm Pentax 645 macro lens
mounted on my Nikon D7100 body using an adaptor. The crop factor is 2.5 x, so I end up with the
"equivalent" of a 300 mm macro lens.
I have a ring light, a ring flash, and a ring light/flash combination unit.
Unfortunately, I only took the last piece of equipment and I found it didn't provide as much supplementary light
as I had hoped for.

CRoy raised an important point- the head can tend to come loose and swivel on you.
I have a couple of centre columns with the platform that the tripod will attach to where I had a machine shop
drill and tap three holes. There is a small set screw in each hole that tightens up against the tripod head
and holds it tight. Some centre columns come with this feature already installed.

If you have a 2 times teleconverter for the 90 mm macro, that might come in handy.
I would forget the zoom lenses.
Hope for an overcast day because on a bright sunny day the contrast can be horrible!

I have numerous tripods, but my favourite is a Gitzo, which is also about 30 years old. Last year I had to replace a set of seals inside the legs because it was starting to slip.
It works fine now. I use those legs with two different ball heads- one is a huge Manfrotto head with a built-in quick release system.
The other is a Linhoff head that is probably at least 70 years old which did not include a quick release system.
As someone suggested previously, I simply added a Manfrotto quick release bracket to the head, and quick release plates to various camera equipment
and it works well.
If you like what you have, there is no need to replace the legs or the head- just add a quick release bracket.

Revhen, the original poster, probably had no idea that he was kicking a hornet's nest when he started this thread with an innocent question.

Has anyone on the forum used a medium format lens with one of the Tilt-Shift adaptors to use it on a smaller format DSLR?
I have a "normal" adaptor (not T.S.) and regularly use Pentax 645 lenses on my Nikon D7100.
The crop factor is 2.5 x.

Gene51 said "Tilt lenses can also be used to minimize depth of field, not just maximize."

Agreed. The Tilt feature is used to control or manipulate the depth of field in general.
For my type of shooting, I would be using it to maximize the depth of field.
On the other hand, I've seen some images where people are looking far a "toy camera" effect,
and they have used the Tilt feature to minimize the DOF.

Is there a general consensus that it is better to do the fixing of converging lines
in the camera (by whatever method) versus in the computer?

Architect1776
Thanks for enlightening me- so the Nikon PC lenses can only shift- and that only up and down, not sideways.
A true Tilt and Shift lens then is much better than a PC lens.

Kmgw9v wrote:
"Only recently Nikon produced a TS lens. And that was the original question about TS not a PC lens. Huge difference between the 2."

Dear Kmgw9v,
What is your understanding of the difference between a "Perspective Control" lens and a "Tilt-Shift" lens?
My understanding is that they are exactly the same thing, just called a different name.
It is the same as Nikon calling a lens a "Micro" lens, while everyone else calls it a "Macro" lens.

A 4th option for the original poster is to buy a large format camera (4 x 5) or (8 x 10) which will have more adjustments
than any PC or TS lens.
If you want to shoot digital, however, a digital back for an 8 x 10 camera can cost over $100,000 U.S.
I have three 4 x 5 cameras and still use them with film.