Everything wrong with the AMX-30, AMX-32 and AMX-40 series of vehicles

Machinery of War Discussion Ground Vehicle
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Do we have any info about Castor thermal camera‘s FoV data？I remember Gaijin accept magnification approximate value by calculating the formula with FoV

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I wish these got their psuedo-stabilizers

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You mean the FCS that can decide to shoot when the gun is aligned with the firing position even when moving ?
Yeah, that’d need FCS to be implemented sadly

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With every accepted bug report they take forever. This is how it would be though with composites. Taken from the first dev server the AMX-40 appeared in. AMX 40 Dev Server Composite - Album on Imgur

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I think its a bit shameful we have 1 AMX-40 despite them having quite some decent differences (Nothing really extreme, but differences in gameplay nonetheless) while other nations can get dumped with variants

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I feel you forgot about the 20mm autocannon ammunition. Community Bug Reporting System

Independent use of the 20mm. Community Bug Reporting System

Also, is there a reason why amx-30/32 transmissions have slow reverse shifting speed when going downhill? Community Bug Reporting System

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Magach moment.

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That “magnification ≈ NFOV_FOV / WFOV_FOV × (high-mag)” shortcut only works if a bunch of things are true at the same time:

  1. the same detector size is used in both fields,
  2. the scan/amplitude on the detector is the same in both fields,
  3. the same eyepiece/display geometry is used, and
  4. the change from WFOV→NFOV is purely a change of effective focal length.

Thermal sights usually fail one or more of those. In practice:

    1. Detector/scan window often changes. Dual-FOV TI systems sometimes crop the detector or use a smaller scan amplitude in NFOV to keep resolution/MTF acceptable. If the scanned width changes, FOV no longer scales exactly as 1/f.
    1. Different scan amplitudes. With rotating/oscillating scanners, NFOV may use a smaller mirror sweep than WFOV (or vice-versa). Again, FOV ≠ constant×1/f.
    1. Different relay/eyepiece trains. Many vehicle TIs are not “binoculars.” The eye views a CRT/TV or micro-display through an eyepiece, or an optical periscope re-images that display. The quoted “×” is a system (apparent) magnification that depends on the display size and eyepiece, not just the objective focal length. It can differ between WFOV and NFOV.
    1. Afocal converters. Two-field optics often add/remove a Galilean afocal in front of the objective for NFOV. Designers may also change field stops to control vignetting and resolution. The net effect is that FOV reduction and apparent magnification increase are not locked to the same ratio.

The method of deriving the low-mag from the two FOV angles isn’t generally valid for thermal imagers, although it gives easy, often correct, estimates. For step-zoom thermal sights, you need the actual optical prescription (focal lengths + afocal factors), the scanned detector width in each mode, and the display/eyepiece geometry. Without those, any “× from FOV” is at best an approximation and can easily be off by 10–30%.

TL;DR:
The formula only works for simple telescopes. Thermal sights don’t behave that way because their scan size, detector use, field stops, and display optics change between WFOV and NFOV. That’s why you can see things like 8× (10°) WFOV and 16× (6°) NFOV instead of the predicted 5°. Real systems break the scaling, so the formula gives only a rough guess.

However, for warthunder, “magnification ≈ NFOV_FOV / WFOV_FOV × (high-mag)” is good enough.

Also, where did you get AN/VSG-X from? Some references list it alongside the TIS in broader manufacturing or Common Module contexts, but it isn’t described as the TIS, and I have yet to see its specifications.