We present very deep and accurate photometry of the open cluster M35 .
We have observed this association in the Cousins R , I filters , together with the Johnson V filter .
We have covered a region of 27.5 \times 27.5 square arcmin , equivalent to a fifth of the total area of the cluster .
The data range from I _ { c } =12.5 to 23.5 magnitudes , and the color intervals are 0.4 \leq ( V–I ) _ { c } \leq 3.0 , 0.5 \leq ( R–I ) _ { c } \leq 2.5 .
Roughly , these values span from 1.6 M _ { \odot } down to the substellar limit , in the case of cluster members .
By using the location of the stars on color-magnitude and color-color diagrams , we have selected candidate members of this cluster .
We have merged our sample with previously published data and obtained a color-magnitude diagram for the complete stellar population of the cluster , covering the spectral range early B – mid M. Based on the distribution of field and cluster stars in color-magnitude and color-color diagrams , we estimate that two thirds of these candidates are likely to be true members of M35 .
These stars approximately double the number of stars identified as candidate members of this cluster ( \sim 2700 ) .
We provide the photometry and accurate positions of these stars .
The deep photometry has allowed us to study the mass segregation within the cluster , the Luminosity Function and Mass Function .
We show that in the magnitude range 13 \leq I _ { c } \leq 22 there is a reduced mass segregation , in opposition to what happens to higher mass stars , where the mass segregation is stronger .
The Luminosity Function behaves essentially as the one characteristic of the Pleiades , presenting a peak at I _ { c } \sim 19 magnitudes ( M _ { I } \sim 9 ) .
Combining our photometry with previous data corresponding to more massive stars , we find that the Mass Function increases monotonically , when plotted in a log-log form , until it reaches \sim 0.8 M _ { \odot } ( \alpha =2.59 ) .
It remains shallower for less massive stars ( \alpha =0.81 for 0.8–0.2 M _ { \odot } ) , whereas a decrease ins observed for stars close to the substellar regime .
These different behaviors suggest that at least three mechanisms play a role in the formation of stellar and substellar objects .
The total mass of the cluster is \sim 1600 M _ { \odot } in the area covered by this study .