Will non-Ai lenses allow TTL auto flash metering on Nikon F4?

I have original non-Ai Nikkor 20mm f3.5 UD and 50mm f1.4 S Auto. When I tried auto TTL flash on Nikon F4 with SB-22S, it was not firing. But it was firing in Manual mode. The flash icon inside the viewfinder was blinking continuously when in Auto TTL mode. What would be the reason? Does non-Ai lenses not support TTL flash feature on Nikon F4?

You have some other issues other than trying to use this flash in the TTL mode.

This flash will not cover the angle of few your 20 mm lens has. Its maximum angle of view is that of a 35 mm lens or 28 mm lens if you use the "wide adapter". If you are using that flash for "flash fill" and not that concerned with uniformity, then it will cover enough of the 20 mm field of view.

The better question is, does the F4 support non-AI lenses. The viewfinder does not have a meter coupling pin that is needed to tell the light meter which lens aperture you are using. Instead it uses the AI meter coupling lever which can be moved out of the way when using non-AI lenses, but requires you to meter in the stop down mode, tedious to say the least.

I suggest you look on page 86 of your user manual to see exactly what lenses are supported by your F4 Nikon and 87 for the conditions under which certain lens types can be used with your cameras meter.

Pages 79, 80 and 81 discuss the use of various flash units including the SB22, but not the SB22S

I have had all my older non-AI lenses converted to AI, so that has allowed me to use them on not just my Nikon F4, but on the Nikon D100, D200 and now D300 and D3.

As I recall, it cost about $25 per lens to have that conversion made. Check with your local camera repair shop and see if they can make that conversion for you.