ok, having been there, THIS is funny.

great. may it serve you well!

usually, YES.
That said, a very severe distortion correction will very slightly soften the pushed pixels, so if critical sharpness is needed and I think I can live with a little barrelling at the edges, etc, I may unclick the box.

Also, sometimes the auto de-fringing is not adequate, so i will turn that off and very carefully dial in the exact color range and amount of fringe correction i need.

just throwing a datapoint out there. I use Costco for school dances and parties where i need to turnaround in 1-2 days. They are easy to upload and pick up the same day or next day in store.
That said, every single order to date has needed to be re-done, usually because of very crushed blacks or just overall too dark images. I did have a couple of very large prints(landscapes) that were way too light, not even in the ballpark.

Costco is happy to reprint the order, and even within minutes while you wait, imo.

There is an option for "auto adjust" which I always check yes. This is so that if I get them and they are wrong, they wont say, "well, that is on you because you didnt let us apply our auto adjust...yadda"

So, I always treat my Costco experience as a two part process; nevertheless, i save money and they are still quicker than my usual print houses.
ymmv

hey, if using a TC is not for YOU, then simply don't use one. You cannot declare they do not have value for others who appreciate their utility.

seriously, why do you persist?

yes, but whatever computational restoration you apply to one, may also be applied to the uncropped image, resulting in improvements to both.

yes, but versus cropping, where you are deleting 50% of your pixels and enlarging what is left...everything is a tradeoff

of course, if your gear is inadequate to begin with, you may not be able to expect much. Just do not be quick to think there is not a case for TC's for the rest of us.
struck a nerve, have we?

yes, for 1.4x TC, you lose one stop of light. I generally make that up by increasing ISO by 2/3rds stop and opening aperture by 1/3 stop when mounting the TC. Shutter stays the same, so fast moving subjects will still render same motion as without TC.

Some folks are quick to dismiss TC's without considering when a TC is to be used.

If your subject does not adequately fill the frame and you would otherwise be cropping the image, THIS is the right time to consider your TC. If you are using a decent lens and an adequate TC, you should expect the lens/TC combination to yield a sharper magnification of image than cropping and enlarging the lens-only image (to match the image size).

I do not shoot Nikon, and I cannot comment on any specific model performance. Of course, there can be a range of quality between various models, just as with lenses.
(BTW: OP, clever use of your broken TC as an extension tube)

People who dismiss, take the time to actually shoot a comparison study and be enlightened. There is a reason the best wildlife photogs use TCs. the end.

agree that shifting to FX should come at a time when you can change out all of your lenses to FX. You are actually doing a disservice to use DX lenses in crop mode on an FX body.

Many people think they need FF but really do not understand why nor have the skills to capitalize on the advantages provided by the larger sensor size. Not knocking the OP at all because he is not the one who has done this, lol.

replying to OP,

sure, i have a couple of vests and they serve me well.
I got over the "fashion" embarrassment years ago - yes, sometimes strangers point and chuckle, but why should you care?
The modern photo vests have better designed pockets, so it is not just for film cans. I carry a few lenses and my handheld flash, a stack of filters, extra cloths and lenscaps, etc, etc in mine and in time it is easy to remember which pocket holds what without fumbling around.

whoa, that is some serious treatment and the Pentax stands up!

I'm definitely on board with older and vintage glass. I still have a small collection of Takumars, komine, tokina, helios, etc...several of which are just stunning in their rendering.

never trust any single review, but the general consensus of many should be fine.