As far as I know they are identical. What you are seeing is the difference between the Ultron lens with its built in (and removable) hood mounted and with it unmounted. I prefer it mounted but some may like it without the hood as it is more compact though naturally the front element is more exposed. I am not sure how much flare this induces. It is not clear why one seller is showing the lens without hood since as far as I know Voigtlander always includes it with the lens not as an optional extra. Though their policy may have changed?????
Unlike many other lens hoods this one has an internal thread on the hood matching an external thread on the lens front - not the other way around which is usual (i.e. where hoods utilize the lens filter thread). I have owned one for a few years now and like the lens which does its job well.
This review seems to me to be balanced. https://phillipreeve.net/blog/review...tron-28mm-2-0/
Some people are critical of this lens from time to time but I think that to be ill informed as for its price it is very well designed and made. As the above review points out flatness of field is not a feature of this lens. But the same can be said for most other lenses in its class, unless you are willing to pay for Leica glass or something of that calibre. In any event since most people stop down the lens to shoot landscape images that criticism is not, in practice, a problem as depth of field takes care of it.