While I don't regret switching a thesis to KOMA script, I do (sometimes) regret stopping using the caption package even though it works fine with scrreprt! I need a solution that won't require using the caption package. Here is an MWE:
\documentclass{scrreprt}
\KOMAoption{captions}{tableheading, figuresignature}
\usepackage{graphicx}
\usepackage{lipsum}
\makeatletter
\newcommand\NOcaption[1]{%
\renewcommand*{\figureformat}{}
\renewcommand*{\tableformat}{}
\renewcommand*{\captionformat}{}
\addtocounter{\@captype}{-1}
\caption{#1}}
\makeatother
\begin{document}
\listoffigures
\listoftables
\clearpage
\lipsum[1]
\begin{table}[ht]
\centering
\NOcaption{}
\begin{tabular}{c}
A table
\end{tabular}
\end{table}
\lipsum[2]
\begin{figure}[ht]
\centering
A figure
\NOcaption{}
\end{figure}
\lipsum[3]
\end{document}
Using the above combination, the caption does not appear in the main text, however, there's an entry for the figure/table in the lists.
Edit:
The whole point of defining a new command NOcaption is to save my self from renewing figureformat, tableformat and captionformat at every table or figure. It was taken from this question. I can see why this is a bit confusing because the correct definition should be:
\makeatletter
\newcommand\NOcaption{% %NO arguments any more.
\renewcommand*{\figureformat}{}
\renewcommand*{\tableformat}{}
\renewcommand*{\captionformat}{}
\addtocounter{\@captype}{-1}
\caption{}}
\makeatother
Then I would just use \NOcaption instead of \NOcaption{}
Putting things in terms of the caption package, I'm looking for an equivalent of list=no in KOMA scrpt, see this answer.
Edit: I should have put this in the MWE, I'm also using hyperref and hypcap. This is why I'm trying to put an 'empty' caption in the first place as hypcap gives an error if no caption was found.
Package hypcap Error: You have forgotten to use \caption.
\usepackage{hyperref}
\usepackage[all]{hypercap}

\captioninside\Nocaptionbut put the text inside a\parboxor whatever. – Axel Sommerfeldt Jan 10 at 20:38\caption? – David Carlisle Jan 10 at 20:39\newcommand\NOcaption{\begingroup\def\addtocontents##1##2{}\expandafter\endgroup\caption}(not guaranteed). – tohecz Jan 10 at 20:44\parbox{\linewidth}{#1}(or something else) instead of\caption{#1}? – Axel Sommerfeldt Jan 10 at 20:49