The VHS format came in 3 varieties: large VHS tapes, small VHS tapes that were usually played back in a VCR by using an adapter, and the semi-pro S-VHS format which only plays back on decks that were designed for that format. The manufactures were brilliant enough to make S-VHS-C camcorders which recorded great quality, but could only be played back in the camcorder because standard VHS decks cannot play S-VHS tapes, usually to the surprise of the camcorder owner after recording on the included S tape.
There is also 3 recording speeds of VHS, and a quality drop with each extension of the recording time. It is crucial to match the brand of the original recorder with a playback deck to get a clear picture when playing back the extended speeds (LP, EP, SLP). The playback speed is displayed on some VCRs, otherwise you will only know if you put a tape in and are still watching content 3 hours later. Most standard size VHS can hold up to 6 hours, there were some longer ones released that could hold more, but the most a VHS-C tape could hold is 2 hours.
We can usually get stable playback and a decent picture image, but it is the extended play recordings that will at times have tracking or other playback issues. We will keep trying different brands to find the one that plays these tapes to the best quality possible, but that sometimes means less than perfect. However, we have recovered images and sound from tapes that other tape converters claimed were blank or lost. Sometimes because they are S-VHS and sometimes because they will only play on one specific brand of VCR, and we may be the only ones who know or care enough to do this and keep all of the major brands around for this reason.
One Tape to One DVD : $15 for 1 hr
Over One hour onto same DVD : $18