There are three steps to get an approximation.
First, get the prices of them in 1961 at
http://www.wheeldon.plus.com/rollei.htm.
Then, convert the figures into present prices at
http://uwacadweb.uwyo.edu/numimage/Currency.htm.
Finally, convert the figures into today's HKD at
http://hk.finance.yahoo.com/currency/convert?amt=0&from=USD&to=HKD.
Here are a sample of the answers. I take the prices of cameras with exposure meter excluding tax.
Models 1961(GBP)
T (Tessar) 88.11.6
3.5F (Xenotar) 105.17.0
3.5F (Planar) 115.4.9
2.8F (Xenotar) 124.9.0
2.8F (Planar) 133.10.9
Wide 147.17.0
Tele 155.5.0
Models 2008(HKD)
T (Tessar) 16,889.5307
3.5F (Xenotar) 20,183.5423
3.5F (Planar) 21,973.5183
2.8F (Xenotar) 23,730.1893
2.8F (Planar) 25,462.9928
Wide 28,192.0648
Tele 29,603.1266
Due to the infinite variety of ways to achieve the second step, i call it a sample of answers. There are many such calculators online. One of the many examples is at
http://www.measuringworth.com/ukcompare/.