I am writing descriptions of the film cameras in my own collection, but English is my second language so I decided to hire a translator for this job. There are several translators available to hire, so I asked them to translate the same sentence from Russian to English. Please could you help me to choose the best translation, which sounds most natural for native speakers: 1) "The Zenit-18 has an electronically controlled breech-block with a vertical slide shutter that was innovative at the time of its release." 2) "Zenit -18 has the most advanced for its time electronically controlled louvered shutter with vertical travel." 3) "Zenit-18 has the newest for its time electronically controlled louver shutter with vertical retrace." 4) "Zenit-18 has the latest for its time electronically controlled vertical-travel louver shutter." 5) "Zenit-18 has a state-of-the-art electronically controlled vertical-travel louvre shutter." Thank you very much for your help!