Why was there a New Turret
Development of the Tiger 1 was completed while it was already in service. Design changes were made at a relatively high rate during the tank's first year of production. In mid 1943 there was a large number of pending changes for the turret, and it was decided to introduce them all together in a "New Turret". The tank's hull did not change at this time.
Changes to the roof
A new cupola was introduced. It had a slanted face and was welded into the roof for impact protection. Seven periscopes provided all-round vision. Rather than opening upwards, the hatch would rise and then swing forwards. As the photo shows, this cupola had a low profile.
The fan was moved to a new housing. Placed 15mm to the right of the turret's axis, it had a thicker cover than before, and was more effective because it was directly over the source of fumes. It used the same removable waterproofing cover as the "Early" version.
A disc was added to the center of the loader's hatch, containing a latch so that it could be unlocked from outside. A new cover was designed for the periscope, wider at the front than the back. Both items are indicated in this photo.
Changes to the sides
The side hatch was modified slightly. Chamfers were no longer made in its edges, so that now its face was a simple disc. (This example is not fully closed.)
Behind the Tiger's mantlet, the opening in the front wall was topped by a dust guard formed of three segments. Now, the same items were used at the bottom of the opening too.
The chin of the turret was modified. In this photo, the arrow points to the front corner, which is the only unchanged spot. To the right, a new notch is cut into the protruding crossbar. It allows the underside plate to be welded more easily. The notch continues along the (new) bottom edge of the wall, which has a broad chamfer.
This his how the chin blends into the "Mid" turret side. Almost everything here is different to the "Early" turrets. In particular, the vertical line of weld that terminates the chin is now moved further towards the back of the turret.
The large, complex pistol port of the "Early" turret was replaced by this much simpler port. It was a hole blocked by a metal plug on a chain. The same type of port was being installed in many types of German AFV at that time.
The "Early" turret had, by this time, two small rectangles of steel welded on its chin to cover the turret locking slots. The "Mid" turret did not have anything like them.
The first modifications
Despite the Germans' determination to settle outstanding issues with the "New turret", some changes were made to it almost immediately.
A partial ring was added to the cupola, welded on top of the periscope covers, to mount an anti-aircraft MG on a sliding mount. (This wrecked Tiger is lacking the plug of its pistol port.)
Very soon afterwards, this ring was "mirrored" and the hatch was made to swing backwards instead of forwards. The position of the hatch hinge was unchanged.
The next change, apparently, was a widening of the slots in the side vision ports.
Further changes occurred later in the "Mid" period and the following "Late" period, but they are out of scope for this article.