Everything about these findings may seem pretty logical, but how do we account for the striking differences between the faces shown in the two photographs we’ve been introduced to thus far? There are two simple factors to account for this: weight gain and lens position/lighting.
Forensic analysis has stated that the early image of Joseph Smith shows a man in his mid 30’s weighing approximately 180 pounds (see Tracy, S. Michael, Millions Shall Know Brother Joseph Again, 221). This weight may be consistent with a fresh-out-of-Liberty-Jail Joseph Smith, but when the second photo was taken, most likely during the Nauvoo period (according to Joseph Smith III, it was in 1843, perhaps only months prior to the Prophet’s martyrdom), Joseph was considered “portly” to his contemporaries, weighing over 200 pounds.
When a person gains weight, particularly a man, much of that weight change becomes first apparent facially upon the chin or beneath it, as well as upon the cheeks. This is factor number one to consider in comparing the early and late pictures of the Prophet Joseph.
The second factor is that of lens position and/or focus. In the early image it should be noted that the entire subject is in focus and that there is no “flattening” to render his features unrealistic. Such modernly-undesirable effects would be the result of artistic photographic tactics employed to make the subject appear more grand, or “bigger than life,” though today such an output is considered undesirable. Such tactics include the position of lighting, the angle of the face, the angle of the lights on the face, etc.
Early daguerreotype camera setups used a primitive lens apparatus with a f-stop rating near 44, which meant that photographed subjects had to remain motionless for upwards of several minutes to appear even dimly in a finished image. Despite such limitations, the detail preserved and lack of distortion in the image was a modern marvel of the age. Later innovations would include reversal prisms for correcting lateral reversal (as discussed earlier) and lenses capable of lower f-stop ratings (meaning exposure times in the area of dozens of seconds instead of minutes). These newer lenses allowed for the creative flair of shallow depth of field in photos but also sometimes caused visual distortion of the subject. In the hands of a frontiersman photographer in Nauvoo, such experimental technologies could indeed have proved somewhat distortional to the finished product.
Consider the two images furnished below by the author. One of them is an “early” image taken around 140 pounds with a simple lens and a wide depth of field and direct sunlight; the other is a “later” image taken around 180 pounds (a 40-pound difference, similar to Joseph Smith) with, additionally, a lens set to a long focal length, which factor tends to the reduction of depth of field, and softened indoor lighting. It is obvious that, though the two images show significant differences in general appearance, similar to the early and later Joseph Smith photos, the proportions of features fixed to the skull (i.e. not fatty areas) remain equal with respect to one another.
(Interestingly, I was unable to get the vertical spacing of the modern subject [top two photos] to line up due to the faces being pointed in slightly different directions; whereas the Joseph Smith photos lined up perfectly with no alterations. The width of his nose and mouth are also perfectly consistent between photos.)