TAMRON
Model 44A
Compact
CF Macro
Zoom
Adaptall-2 Symbol28~70mmF/3.5-4.5
Compact CF Macro Zoom
Tamron Adaptall-2 28-70mm F/3.5-4.5 Model 44A Lens
[No photo of optical layout is presently available.]

Tamron 28-70mm F/3.5-4.5 Model 44A: Autofocus camera bodies and their accompanying autofocus lenses had already become all the rage when Tamron's 28-70 model 44A and the 70-210 model 46A lenses were introduced in 1986. Tamron correctly anticipated that sales of these two manual focus lenses would be moderate, and designed these two lenses to be as cost effective possible to manufacture. This lens, like its telephoto zoom sibling, incorporates high strength plastic instead of metal wherever possible. The focus and zoom collars are made of plastic and feature integral knurled plastic grips.

While both lenses looked and felt a bit cheap, there was no compromise in optical performance since Tamron wasn't willing to sacrifice optical quality in the pursuit of additional cost saving measures. Overall optical performance is somewhat above average and yields good to very good results at F/5.6 and smaller apertures. Optimal aperture is F/8 or F/11 depending on the zoom setting. The 28-70's optical design borrows heavily from the SP 35-80 F/2.8-3.8 and incorporates the same basic features. Like the SP 35-80, this lens features a maximum macro magnification at the telephoto focal length and incorporates the Minimum Object Distance (M.O.D.) selector system whereby turning the focus ring to the minimum focus distance causes the zoom ring to automatically move to the telephoto position. This lens, as with the SP 35-80, has a slight excess of barrel distortion between the wide angle to normal zoom range.

Lens Specifications:

Lens Model 44A
Focal Length 28 — 70mm
Aperture Range f/3.5~4.5 — 22, AE
Angle of View 75°~34°
Optical Construction
(Groups / Elements)
8 / 8
Min. Focus from Film Plane 11.8" (0.3m)
Macro Mag. Ratio [w/2X Converter] 1:3.15 [?]
Filter Size 62mm
Diameter 2.7" (69mm)
Length at
[w/Nikon mount]
2.7" (70.4mm)
[2.9" (74.9mm)]
Weight 12.8 oz. (361g)
Lens Hood Bayonet type #86FH, optional.
Accessory Accepts SP 2X tele-converter #01F? **
** We have NOT verified if this lens can indeed accept the SP 2X tele-converter.
Tamron 28-70 F/3.5-4.5
PERFORMANCE
Modern Photo's
Standard
as Tested
Focal length: ±5%
(26.60-29.40mm)
(66.50-73.50mm)
28.98mm
66.95mm
Aperture: ±5%
at 28mm: (f/3.33-3.68)
at 70mm: (f/4.28-4.73)
f/3.52
f/4.61
Distortion:
28mm: (±2.5%)
70mm: (±2.0%)
2.62% (barrel)
0.45% (pincush.)
Light falloff: at f/5.6
+1 stop from theoretical limit
28mm: (0-2.0 stops)
70mm: (0-1.3 stops)
0.7 stops
0.6 stops
Tamron 28-70 F/3.5-4.5
F/no. RESOLUTION
at 28mm
at 1:49 magnification
CONTRAST
at 28mm
(30 lines/mm)
Center
Lines/mm
Corner
Lines/mm
Center % Corner %
3.5 49 39 46 33
5.6 55 44 56 44
8 62 49 58 45
11 62 55 57 42
16 55 49 45 34
22 49 44 39 30
Tamron 28-70 F/3.5-4.5
F/no. RESOLUTION
at 50mm
at 1:50 magnification
CONTRAST
at 50mm
(30 lines/mm)
Center
Lines/mm
Corner
Lines/mm
Center % Corner %
4 56 50 48 36
5.6 63 56 58 46
8 70 56 60 49
11 63 50 61 50
16 56 50 50 40
22 50 45 41 29
Tamron 28-70 F/3.5-4.5
F/no. RESOLUTION
at 70mm
at 1:50 magnification
CONTRAST
at 70mm
(30 lines/mm)
Center
Lines/mm
Corner
Lines/mm
Center % Corner %
4.5 56 45 50 39
5.6 63 50 58 48
8 63 56 60 49
11 70 56 61 49
16 63 50 49 39
22 56 45 39 29
Tamron 28-70 F/3.5-4.5
F/no. MACRO RESOLUTION
at 70mm
at 1:4 magnification
Center
Lines/mm
Corner
Lines/mm
4.5 36 32
5.6 40 36
8 45 36
11 45 40
16 40 36
22 40 32
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